Climate and average weather in Highland
In Highland, the summers are hot, fairly dry, and clear and the winters are cool, snowy, and mostly clear.
Over the course of the year, the temperature in Highland typically varies from 39°F to 89°F, and is rarely below 31°F or above 96°F. August is the hottest month of the year, while December is the coldest.
Based on the travel score, the best times of year to visit Highland for warm-weather activities are from early April to late June and mid September to mid November.
- Hottest
- Aug
- 89°
- Coldest
- Dec
- 39°
- Wettest
- Feb
- 2.7 in
- Driest
- Jun
- 0.1 in
- Rain / yr
- 11.8 in
- 42 wet days
- Daylight
- 9.7–14.3 h
- shortest–longest
- Elevation
- 1,309 ft
- 34.1°N
- Clearest
- Sep
- 15% cloud
Highland is city in San Bernardino County, California, United States.
- Density
- 1,121/km²
- people per km²
- Founded
- 1891
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Highland weather by month, at a glance
The whole year in one picture — sky, rain, humidity, temperature and travel score. Click any band to jump to its full chart.
Each stripe is one measure across the whole year, stacked so a single day reads top to bottom. The sky band runs overcast grey on top down to clear blue at the base — more blue means sunnier — followed by the rainfall curve, the humidity band, a temperature strip that tints each stretch of the year by how warm its average high is, and the travel-score line at the foot. Scan straight down any date to read that day across every measure at once; the score climbs highest around early April to late June.
Temperature through the year
Daily average highs and lows in Highland, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.
The hot season lasts 3.7 months, from June 10 to September 29, with daily high temperatures above 81°F. The hottest month of the year in Highland is August, with an average high of 89°F and low of 65°F.
The cool season lasts 3.6 months, from November 23 to March 11, with daily high temperatures below 62°F. The coldest month of the year in Highland is December, with an average low of 39°F and high of 57°F.
Days typically run about 21°F warmer than nights, with the widest day–night swing (around 25°F) in June.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°F) | 57 | 58 | 62 | 68 | 75 | 83 | 89 | 89 | 85 | 75 | 64 | 57 |
| Avg low (°F) | 40 | 40 | 43 | 46 | 52 | 58 | 65 | 65 | 61 | 53 | 45 | 39 |
| Avg high (°F) | Avg low (°F) | |
|---|---|---|
| Jan | 57 | 40 |
| Feb | 58 | 40 |
| Mar | 62 | 43 |
| Apr | 68 | 46 |
| May | 75 | 52 |
| Jun | 83 | 58 |
| Jul | 89 | 65 |
| Aug | 89 | 65 |
| Sep | 85 | 61 |
| Oct | 75 | 53 |
| Nov | 64 | 45 |
| Dec | 57 | 39 |
How hot and cold Highland really feels
The felt-temperature range through the year — heat index on the day's high (summer humidity), wind chill on the night's low (winter wind). The dashed lines are the plain thermometer; the gap is how much hotter or colder it really feels.
On the hottest afternoons, once humidity is folded in, Highland feels like about 90°F (around July 29). About 5 days a year carry some heat stress, peaking in July.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Feels-like high (°F) | 57 | 58 | 62 | 68 | 75 | 83 | 89 | 89 | 85 | 75 | 64 | 57 |
| Air high (°F) | 57 | 58 | 62 | 68 | 75 | 83 | 89 | 89 | 85 | 75 | 64 | 57 |
| Feels-like low (°F) | 36 | 37 | 40 | 44 | 52 | 58 | 65 | 65 | 61 | 53 | 43 | 36 |
| Air low (°F) | 40 | 40 | 43 | 46 | 52 | 58 | 65 | 65 | 61 | 53 | 45 | 39 |
| Feels-like high (°F) | Air high (°F) | Feels-like low (°F) | Air low (°F) | |
|---|---|---|---|---|
| Jan | 57 | 57 | 36 | 40 |
| Feb | 58 | 58 | 37 | 40 |
| Mar | 62 | 62 | 40 | 43 |
| Apr | 68 | 68 | 44 | 46 |
| May | 75 | 75 | 52 | 52 |
| Jun | 83 | 83 | 58 | 58 |
| Jul | 89 | 89 | 65 | 65 |
| Aug | 89 | 89 | 65 | 65 |
| Sep | 85 | 85 | 61 | 61 |
| Oct | 75 | 75 | 53 | 53 |
| Nov | 64 | 64 | 43 | 45 |
| Dec | 57 | 57 | 36 | 39 |
Average hourly temperature in Highland
A compact picture of the whole year, hour by hour: each column is a day, each row an hour, and the color is the modeled average temperature. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.
Read left to right for the day of the year and top to bottom for the hour of the day; the color is the modeled temperature, cool blues through to hot reds on the same scale as the other charts. A vertical slice is a single day's swing — coolest just before dawn, warmest in the mid-afternoon — while a horizontal slice follows one hour across the seasons. The darker overlay marks night and the lighter one the twilight around sunrise and sunset. Colors run warmest on August afternoons, near 89°F, and coldest before dawn in December, near 39°F.
Highland weather by month
Every month at a glance. Click a month for its detailed page.
| Month | High / Low (°F) | Rainfall (inches) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 57° / 40° | 2.2 | 5.6 | 0.9 | 10 | 4.7 |
| Feb | 58° / 40° | 2.7 | 6.6 | 1.1 | 10.7 | 4.8 |
| Mar | 62° / 43° | 1.6 | 5.7 | 0.9 | 11.7 | 6.2 |
| Apr | 68° / 46° | 0.8 | 3.3 | 0.3 | 12.8 | 7.7 |
| May | 75° / 52° | 0.3 | 2.5 | 0 | 13.8 | 8.7 |
| Jun | 83° / 58° | 0.1 | 0.7 | 0 | 14.2 | 7.8 |
| Jul | 89° / 65° | 0.5 | 2.9 | 0 | 14 | 5.4 |
| Aug | 89° / 65° | 0.4 | 3 | 0 | 13.3 | 5.3 |
| Sep | 85° / 61° | 0.3 | 1.6 | 0 | 12.2 | 7.2 |
| Oct | 75° / 53° | 0.5 | 2.1 | 0 | 11.1 | 8.8 |
| Nov | 64° / 45° | 0.7 | 2.9 | 0.2 | 10.2 | 7.2 |
| Dec | 57° / 39° | 1.7 | 4.6 | 0.5 | 9.8 | 4.7 |
Chance of rain
How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.
Highland gets about 11.8 in of precipitation a year. On a typical day the chance of rain is mostly dry, but that rises and falls sharply with the seasons.
The wetter season lasts 4.5 months, from around Nov 27 to Apr 12, peaking in February at about 26% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Jun 16.
February is the wettest month by volume, with 2.7 in over about 7 wet days; June is the driest, with 0.1 in. Some of the cold-season precipitation falls as snow.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain on a day (%) | 18 | 23 | 19 | 11 | 8 | 3 | 9 | 10 | 5 | 6 | 10 | 15 |
| Rain days | 6 | 7 | 6 | 3 | 3 | 1 | 3 | 3 | 2 | 2 | 3 | 5 |
| Rain on a day (%) | Rain days | |
|---|---|---|
| Jan | 18 | 6 |
| Feb | 23 | 7 |
| Mar | 19 | 6 |
| Apr | 11 | 3 |
| May | 8 | 3 |
| Jun | 3 | 1 |
| Jul | 9 | 3 |
| Aug | 10 | 3 |
| Sep | 5 | 2 |
| Oct | 6 | 2 |
| Nov | 10 | 3 |
| Dec | 15 | 5 |
Monthly rainfall
Over a full year, Highland collects about 11.8 in of rain across 42 wet days — roughly 1.0 in in an average month.
It doesn’t fall evenly. February is the wettest month with 2.7 in, while June is the driest at just 0.1 in. The three wettest months alone bring about 56% of the year’s total, and some of the cold-season precipitation falls as snow.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rainfall (in) | 2.2 | 2.7 | 1.6 | 0.8 | 0.3 | 0.1 | 0.5 | 0.4 | 0.3 | 0.5 | 0.7 | 1.7 |
| Rain days | 6 | 7 | 6 | 3 | 3 | 1 | 3 | 3 | 2 | 2 | 3 | 5 |
| Snow days | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
| Rainfall (in) | Rain days | Snow days | |
|---|---|---|---|
| Jan | 2.2 | 6 | 1 |
| Feb | 2.7 | 7 | 1 |
| Mar | 1.6 | 6 | 1 |
| Apr | 0.8 | 3 | 0 |
| May | 0.3 | 3 | 0 |
| Jun | 0.1 | 1 | 0 |
| Jul | 0.5 | 3 | 0 |
| Aug | 0.4 | 3 | 0 |
| Sep | 0.3 | 2 | 0 |
| Oct | 0.5 | 2 | 0 |
| Nov | 0.7 | 3 | 0 |
| Dec | 1.7 | 5 | 1 |
Snow in Highland
Average snowy days through the year, the snow-season span, and estimated snowfall — for ski trips and the perennial 'will there be snow at Christmas?' question.
Highland averages about 4 snowy days a year. Snow season runs roughly Dec 11 to Apr 8 — about 3.9 months.
February is snowiest, with roughly 1.1 day of snow and an estimated 2 in of snowfall. Over the year that adds up to an estimated 7 in of snow.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Snow days | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
| Snowfall (in) | 1 | 2 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 |
| Snow days | Snowfall (in) | |
|---|---|---|
| Jan | 1 | 1 |
| Feb | 1 | 2 |
| Mar | 1 | 1 |
| Apr | 0 | 1 |
| May | 0 | 0 |
| Jun | 0 | 0 |
| Jul | 0 | 0 |
| Aug | 0 | 0 |
| Sep | 0 | 0 |
| Oct | 0 | 0 |
| Nov | 0 | 0 |
| Dec | 1 | 2 |
Clouds and sunshine
How often the daytime sky is clear, partly cloudy or overcast.
In Highland, the average share of the sky covered by clouds shows significant seasonal variation over the course of the year.
The clearer part of the year begins around April 27 and lasts for 6.6 months, ending around November 13. The clearest month is September, when the sky is clear, mostly clear, or partly cloudy 93% of the time on average.
The cloudier part of the year begins around November 14 and lasts for 5.4 months, ending around April 26. The cloudiest month is February, when it is overcast or mostly cloudy 42% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 61 | 58 | 64 | 75 | 82 | 92 | 89 | 93 | 93 | 86 | 77 | 65 |
| Cloudier (%) | 39 | 42 | 36 | 25 | 18 | 8 | 11 | 7 | 7 | 14 | 23 | 35 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| Jan | 61 | 39 |
| Feb | 58 | 42 |
| Mar | 64 | 36 |
| Apr | 75 | 25 |
| May | 82 | 18 |
| Jun | 92 | 8 |
| Jul | 89 | 11 |
| Aug | 93 | 7 |
| Sep | 93 | 7 |
| Oct | 86 | 14 |
| Nov | 77 | 23 |
| Dec | 65 | 35 |
Daylight, sunrise and sunset
Hours of daylight through the year, with sunrise and sunset times.
The gold band is daylight — sunrise runs along its lower edge, sunset along the upper — so it widens toward summer and pinches toward winter, with night the dark area above and below. The longest day, around June 14, brings about 14 h 18 min of light; the shortest, around December 14, only 9 h 42 min — a swing of roughly 4 h 36 min.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 10.0 | 10.7 | 11.7 | 12.8 | 13.8 | 14.2 | 14.0 | 13.3 | 12.2 | 11.1 | 10.2 | 9.8 |
| Sunrise (AM) | 6:59 | 6:41 | 6:06 | 5:24 | 4:52 | 4:41 | 4:52 | 5:14 | 5:37 | 6:00 | 6:28 | 6:53 |
| Sunset (PM) | 4:57 | 5:25 | 5:51 | 6:15 | 6:38 | 6:57 | 6:57 | 6:31 | 5:49 | 5:08 | 4:40 | 4:37 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| Jan | 10.0 | 6:59 | 4:57 |
| Feb | 10.7 | 6:41 | 5:25 |
| Mar | 11.7 | 6:06 | 5:51 |
| Apr | 12.8 | 5:24 | 6:15 |
| May | 13.8 | 4:52 | 6:38 |
| Jun | 14.2 | 4:41 | 6:57 |
| Jul | 14.0 | 4:52 | 6:57 |
| Aug | 13.3 | 5:14 | 6:31 |
| Sep | 12.2 | 5:37 | 5:49 |
| Oct | 11.1 | 6:00 | 5:08 |
| Nov | 10.2 | 6:28 | 4:40 |
| Dec | 9.8 | 6:53 | 4:37 |
Sunny days
How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.
Highland averages about 20 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 13 and 27 days.
The sunnier stretch runs 5.8 months, from around May 14 to Nov 6. The sunniest month is September, with roughly 27 sunny days (brilliant).
The greyest month is February, down near 14 sunny days — about 48% fewer than the September peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sunny days | 15 | 13 | 15 | 18 | 21 | 25 | 25 | 27 | 26 | 24 | 19 | 16 |
| Sky | Mixed | Mixed | Mixed | Bright | Bright | Brilliant | Brilliant | Brilliant | Brilliant | Brilliant | Bright | Bright |
| Sunny days | Sky | |
|---|---|---|
| Jan | 15 | Mixed |
| Feb | 13 | Mixed |
| Mar | 15 | Mixed |
| Apr | 18 | Bright |
| May | 21 | Bright |
| Jun | 25 | Brilliant |
| Jul | 25 | Brilliant |
| Aug | 27 | Brilliant |
| Sep | 26 | Brilliant |
| Oct | 24 | Brilliant |
| Nov | 19 | Bright |
| Dec | 16 | Bright |
Humidity comfort
Share of days at each humidity comfort level, based on the dew point — the measure that tracks how muggy it actually feels.
Humidity comfort is graded by the dew point — the temperature at which the air would be fully saturated — because it tracks how muggy it actually feels far better than relative humidity does. A low dew point feels dry and crisp; a high one feels sticky and oppressive no matter the reading on a humidity gauge.
In Highland, the air stays dry or comfortable essentially all year. Even in July, the muggiest month, it feels humid or worse only about 7% of the time — humidity is not something you need to plan around here.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 100 | 100 | 100 | 100 | 100 | 97 | 76 | 77 | 90 | 99 | 100 | 100 |
| Comfortable (%) | 0 | 0 | 0 | 0 | 0 | 3 | 17 | 17 | 8 | 1 | 0 | 0 |
| Humid (%) | 0 | 0 | 0 | 0 | 0 | 0 | 7 | 6 | 2 | 0 | 0 | 0 |
| Dry (%) | Comfortable (%) | Humid (%) | |
|---|---|---|---|
| Jan | 100 | 0 | 0 |
| Feb | 100 | 0 | 0 |
| Mar | 100 | 0 | 0 |
| Apr | 100 | 0 | 0 |
| May | 100 | 0 | 0 |
| Jun | 97 | 3 | 0 |
| Jul | 76 | 17 | 7 |
| Aug | 77 | 17 | 6 |
| Sep | 90 | 8 | 2 |
| Oct | 99 | 1 | 0 |
| Nov | 100 | 0 | 0 |
| Dec | 100 | 0 | 0 |
Wind
Average wind speed through the year, banded into plain-language speed zones so a number reads as 'breezy' or 'calm' without knowing the scale.
This is the average sustained wind speed at the standard 10 metres above open ground — the steady flow a weather station reports, not the sharper gusts that come and go, which can run half again as fast. It's the number that says whether a place is generally breezy or calm.
Wind in Highland is steady company: average speeds sit near 4 mph — calm — in every month of the year, with no meaningful windy or calm season.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (mph) | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 |
| Feels | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm |
| Wind speed (mph) | Feels | |
|---|---|---|
| Jan | 4 | calm |
| Feb | 4 | calm |
| Mar | 4 | calm |
| Apr | 4 | calm |
| May | 4 | calm |
| Jun | 4 | calm |
| Jul | 4 | calm |
| Aug | 4 | calm |
| Sep | 4 | calm |
| Oct | 4 | calm |
| Nov | 4 | calm |
| Dec | 4 | calm |
Best time to visit Highland
To characterize how pleasant the weather is in Highland throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.
Around mid April, Highland is still near the start of its best-weather window — great conditions with the peak-season crowds not yet at full swing.
Inferred from the travel-score curve; month-by-month visitor numbers are a planned addition.
The travel score favors clear, rainless days with daytime highs between 64°F and 82°F. Based on this score, the best times of year to visit Highland for general outdoor tourist activities run from early April to late June and again from mid September to mid November, with a peak score in the second week of October.
The travel score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Travel score (0–10) | 4.7 | 4.8 | 6.2 | 7.7 | 8.7 | 7.8 | 5.5 | 5.3 | 7.2 | 8.7 | 7.2 | 4.7 |
| Rating | fair | fair | good | ideal | ideal | ideal | fair | fair | good | ideal | good | fair |
| Travel score (0–10) | Rating | |
|---|---|---|
| Jan | 4.7 | fair |
| Feb | 4.8 | fair |
| Mar | 6.2 | good |
| Apr | 7.7 | ideal |
| May | 8.7 | ideal |
| Jun | 7.8 | ideal |
| Jul | 5.5 | fair |
| Aug | 5.3 | fair |
| Sep | 7.2 | good |
| Oct | 8.7 | ideal |
| Nov | 7.2 | good |
| Dec | 4.7 | fair |
The beach/pool score favors clear, rainless days with daytime highs between 75°F and 93°F. Based on this score, the best time of year to visit Highland for hot-weather activities is from late May to mid October, with a peak score in the third week of June.
The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).
What to pack for Highland, by month
Month by month, what's worth putting in the bag — from the temperature range, rain chance, sun and wind. Tap a month for a quick packing note.
For a warm-season trip around August (highs near 89°F), the essentials are light clothes and sun protection. In the cold season around December (highs near 57°F), pack a warm layer.
In August, Highland sees daytime highs around 89°F and nights near 65°F. Pack light clothes and sun protection. About 3 days see rain.
UV index (midday) in Highland by month
Clear-sky midday UV index through the year, shaded by the WHO exposure levels — how much sun protection each month calls for.
Under clear skies, the midday UV index in Highland peaks around June 23 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 16 at about 3 (moderate).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 11 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 4 | 5 | 5 | 8 | 8 | 11 | 11 | 11 | 8 | 6 | 4 | 3 |
| Level | Moderate | Moderate | High | Very high | Very high | Extreme | Extreme | Extreme | Very high | High | Moderate | Moderate |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 4 | Moderate |
| Feb | 5 | Moderate |
| Mar | 5 | High |
| Apr | 8 | Very high |
| May | 8 | Very high |
| Jun | 11 | Extreme |
| Jul | 11 | Extreme |
| Aug | 11 | Extreme |
| Sep | 8 | Very high |
| Oct | 6 | High |
| Nov | 4 | Moderate |
| Dec | 3 | Moderate |
Average hourly UV index in Highland
Modeled clear-sky UV for every hour of every day — when in the day sun protection actually matters.
The whole year hour by hour: each column is a day, each row an hour, and the color is the modeled clear-sky UV index — the midday peak scaled down as the sun sits lower in the sky. Darker overlays mark night, lighter ones the civil-twilight hours around sunrise and sunset.
UV falls off far faster than brightness as the sun drops, so even in June the burn window is concentrated in the middle of the day: about 8.5 hours a day reach index 3 (protection recommended), and 6 hours reach 6 or more. Mornings and late afternoons stay comparatively gentle year round.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV ≥ 3 (h/day) | 3 | 4.5 | 5.5 | 7 | 8 | 8.5 | 8.5 | 8 | 7 | 5.5 | 3 | 0 |
| UV ≥ 6 (h/day) | 0 | 0 | 0 | 3.5 | 4.5 | 6 | 6 | 5.5 | 4 | 0 | 0 | 0 |
| UV ≥ 3 (h/day) | UV ≥ 6 (h/day) | |
|---|---|---|
| Jan | 3 | 0 |
| Feb | 4.5 | 0 |
| Mar | 5.5 | 0 |
| Apr | 7 | 3.5 |
| May | 8 | 4.5 |
| Jun | 8.5 | 6 |
| Jul | 8.5 | 6 |
| Aug | 8 | 5.5 |
| Sep | 7 | 4 |
| Oct | 5.5 | 0 |
| Nov | 3 | 0 |
| Dec | 0 | 0 |
Air quality in Highland by month
Average fine-particle pollution (PM2.5) through the year — so you can see which months the air is worst, not just the yearly average.
Air quality in Highland is worst in September — around 30 µg/m³ PM2.5 (moderate), about 5.3× the cleanest month (December, 6 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 6 | 7 | 9 | 9 | 9 | 16 | 12 | 15 | 30 | 7 | 6 | 6 |
| Level | Good | Good | Good | Good | Good | Moderate | Good | Moderate | Moderate | Good | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 6 | Good |
| Feb | 7 | Good |
| Mar | 9 | Good |
| Apr | 9 | Good |
| May | 9 | Good |
| Jun | 16 | Moderate |
| Jul | 12 | Good |
| Aug | 15 | Moderate |
| Sep | 30 | Moderate |
| Oct | 7 | Good |
| Nov | 6 | Good |
| Dec | 6 | Good |
Growing season
Highland is mild enough that a frost-free day stays more likely than not even in midwinter. Nights are reliably above freezing from about December 30 to December 15 (351 days); outside that window a hard frost is an occasional risk.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Frost-free chance (%) | 93 | 93 | 97 | 99 | 100 | 100 | 100 | 100 | 100 | 100 | 99 | 91 |
| Frost nights | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 17 |
| Frost-free chance (%) | Frost nights | |
|---|---|---|
| Jan | 93 | 2 |
| Feb | 93 | 0 |
| Mar | 97 | 0 |
| Apr | 99 | 0 |
| May | 100 | 0 |
| Jun | 100 | 0 |
| Jul | 100 | 0 |
| Aug | 100 | 0 |
| Sep | 100 | 0 |
| Oct | 100 | 0 |
| Nov | 99 | 0 |
| Dec | 91 | 17 |
Growing degree days
Growing degree days tally heat above 50°F: each day adds however many degrees its average temperature runs over that threshold, and cold days add nothing. Highland banks about 4,246 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around August.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Growing degree days (°F·days) | 0 | 0 | 81 | 206 | 409 | 622 | 827 | 847 | 684 | 434 | 136 | 0 |
| Growing degree days (°F·days) | |
|---|---|
| Jan | 0 |
| Feb | 0 |
| Mar | 81 |
| Apr | 206 |
| May | 409 |
| Jun | 622 |
| Jul | 827 |
| Aug | 847 |
| Sep | 684 |
| Oct | 434 |
| Nov | 136 |
| Dec | 0 |
Solar energy
Average daily shortwave solar energy reaching the ground, banded into brightness zones so the number means something at a glance.
Solar energy is how much sunlight actually reaches the ground each day, measured in kilowatt-hours per square metre (kWh/m²) — the combined effect of how long the sun is up, how high it climbs, and how much cloud gets in the way. It's the raw fuel a solar panel has to work with: for scale, 1 kWh/m² a day is dim and wintry, while 7+ is desert-bright.
Highland receives about 5.8 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 3.0 and 8.4 kWh/m².
The brighter stretch of the year lasts 6.3 months, from around Mar 20 to Sep 28. The brightest month is June, averaging about 8.3 kWh/m² (intense).
The dimmest month is December, down near 3.0 kWh/m² — roughly 64% less than the June peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 3.2 | 4.1 | 5.6 | 6.9 | 7.7 | 8.4 | 7.9 | 7.3 | 6.3 | 4.9 | 3.7 | 3.0 |
| Level | Moderate | Bright | Bright | Intense | Intense | Intense | Intense | Intense | Intense | Bright | Moderate | Moderate |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| Jan | 3.2 | Moderate |
| Feb | 4.1 | Bright |
| Mar | 5.6 | Bright |
| Apr | 6.9 | Intense |
| May | 7.7 | Intense |
| Jun | 8.4 | Intense |
| Jul | 7.9 | Intense |
| Aug | 7.3 | Intense |
| Sep | 6.3 | Intense |
| Oct | 4.9 | Bright |
| Nov | 3.7 | Moderate |
| Dec | 3.0 | Moderate |
Where is Highland?
Highland sits at 34.1°N, 117.2°W, 1,309 ft above sea level, in United States. The nearest listed city is San Bernardino, 5.0 mi away.
Topography around Highland
How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Highland.
Within 2 miles, the terrain around Highland has significant variations in elevation — a maximum elevation change of 1,558 ft around an average of 1,394 ft above sea level; within 10 miles, very significant variations in elevation — a maximum elevation change of 6,699 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 11,411 ft.
The land around Highland is covered by artificial surfaces (57%) within 2 miles, trees (28%), artificial surfaces (28%) and shrubs (24%) within 10 miles, and shrubs (29%) and bare terrain (21%) within 50 miles.
United States travel facts
- Power plugs
- Type A / B
- 120 V · 60 Hz
- Prices
- ≈ 100% of US
- price level, 2025
- GDP per capita
- $90,027
- 2025
- Happiness
- 6.8 / 10
- World Happiness, 2025
- Safe drinking water
- 98%
- of population, 2024
- Homicide rate
- 5.8
- per 100k, 2023
- Road deaths
- 12.7
- per 100k/yr, 2019
- Income group
- High
- World Bank
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Highland (34.1283°, -117.2087°, elevation 1,309 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).