Climate and average weather in Idaho Falls
In Idaho Falls, the summers are hot, fairly dry, and mostly clear and the winters are very cold, snowy, and partly cloudy.
Over the course of the year, the temperature in Idaho Falls typically varies from 17°F to 87°F, and is rarely below 1°F or above 96°F. July is the hottest month of the year, while January is the coldest.
Based on the travel score, the best times of year to visit Idaho Falls for warm-weather activities are from late May to early July and mid August to early October.
- Hottest
- Jul
- 87°
- Coldest
- Jan
- 17°
- Wettest
- May
- 2.1 in
- Driest
- Jul
- 0.5 in
- Rain / yr
- 15.0 in
- 88 wet days
- Daylight
- 8.8–15.2 h
- shortest–longest
- Elevation
- 4,705 ft
- 43.5°N
- Clearest
- Jul
- 31% cloud
Idaho Falls is city in and county seat of Bonneville County, Idaho, United States.
- Density
- 988/km²
- people per km²
- Founded
- 1864
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Idaho Falls 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 mid August to early October.
Temperature through the year
Daily average highs and lows in Idaho Falls, from 1991–2020 of climate data. The shaded bands show the range most days fall in — 10th to 90th percentile.
The hot season lasts 3.2 months, from June 10 to September 15, with daily high temperatures above 73°F. The hottest month of the year in Idaho Falls is July, with an average high of 87°F and low of 57°F.
The cool season lasts 3.4 months, from November 19 to March 2, with daily high temperatures below 41°F. The coldest month of the year in Idaho Falls is January, with an average low of 17°F and high of 31°F.
Days typically run about 22°F warmer than nights, with the widest day–night swing (around 30°F) in July.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°F) | 31 | 36 | 47 | 56 | 66 | 76 | 87 | 85 | 74 | 58 | 43 | 31 |
| Avg low (°F) | 17 | 21 | 29 | 34 | 42 | 50 | 57 | 55 | 47 | 36 | 26 | 18 |
| Avg high (°F) | Avg low (°F) | |
|---|---|---|
| Jan | 31 | 17 |
| Feb | 36 | 21 |
| Mar | 47 | 29 |
| Apr | 56 | 34 |
| May | 66 | 42 |
| Jun | 76 | 50 |
| Jul | 87 | 57 |
| Aug | 85 | 55 |
| Sep | 74 | 47 |
| Oct | 58 | 36 |
| Nov | 43 | 26 |
| Dec | 31 | 18 |
How hot and cold Idaho Falls 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 coldest nights, wind chill pulls the feels-like down to about 7°F (around December 30), with roughly 199 freezing days a year (feels-like at or below 32°F) — 87 of them bitterly cold — worst in December.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Feels-like high (°F) | 31 | 36 | 47 | 56 | 66 | 76 | 87 | 85 | 74 | 59 | 43 | 31 |
| Air high (°F) | 31 | 36 | 47 | 56 | 66 | 76 | 87 | 85 | 74 | 58 | 43 | 31 |
| Feels-like low (°F) | 9 | 13 | 21 | 28 | 38 | 48 | 57 | 55 | 44 | 31 | 19 | 9 |
| Air low (°F) | 17 | 21 | 29 | 34 | 42 | 50 | 57 | 55 | 47 | 36 | 26 | 18 |
| Feels-like high (°F) | Air high (°F) | Feels-like low (°F) | Air low (°F) | |
|---|---|---|---|---|
| Jan | 31 | 31 | 9 | 17 |
| Feb | 36 | 36 | 13 | 21 |
| Mar | 47 | 47 | 21 | 29 |
| Apr | 56 | 56 | 28 | 34 |
| May | 66 | 66 | 38 | 42 |
| Jun | 76 | 76 | 48 | 50 |
| Jul | 87 | 87 | 57 | 57 |
| Aug | 85 | 85 | 55 | 55 |
| Sep | 74 | 74 | 44 | 47 |
| Oct | 59 | 58 | 31 | 36 |
| Nov | 43 | 43 | 19 | 26 |
| Dec | 31 | 31 | 9 | 18 |
Average hourly temperature in Idaho Falls
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 July afternoons, near 87°F, and coldest before dawn in January, near 17°F.
Idaho Falls 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 | 31° / 17° | 1.4 | 9.4 | 10.3 | 9.1 | 0.0 |
| Feb | 36° / 21° | 1.1 | 7.8 | 7.3 | 10.2 | 0.0 |
| Mar | 47° / 29° | 1.4 | 9.2 | 4.6 | 11.6 | 1.6 |
| Apr | 56° / 34° | 1.8 | 11.2 | 3 | 13.2 | 3.7 |
| May | 66° / 42° | 2.1 | 9.6 | 0.8 | 14.5 | 6.1 |
| Jun | 76° / 50° | 1.2 | 6 | 0.1 | 15.2 | 7.5 |
| Jul | 87° / 57° | 0.5 | 3.3 | 0 | 14.9 | 5.9 |
| Aug | 85° / 55° | 0.5 | 3.5 | 0 | 13.8 | 6.5 |
| Sep | 74° / 47° | 1.0 | 4.2 | 0.1 | 12.3 | 8.0 |
| Oct | 58° / 36° | 1.3 | 6.5 | 1.2 | 10.8 | 5.0 |
| Nov | 43° / 26° | 1.2 | 7.4 | 5.5 | 9.5 | 0.7 |
| Dec | 31° / 18° | 1.5 | 9.4 | 9.7 | 8.8 | 0.0 |
Chance of rain
How likely it is to rain on a typical day, and how that shifts across the wetter and drier seasons.
Idaho Falls gets about 15.0 in of precipitation a year. On a typical day the chance of rain is some rain, but that rises and falls sharply with the seasons.
The wetter season lasts 6.8 months, from around Nov 16 to Jun 11, peaking in April at about 37% chance on a given day. The drier stretch runs the rest of the year, bottoming out around Aug 10.
May is the wettest month by volume, with 2.1 in over about 10 wet days; July is the driest, with 0.5 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 (%) | 30 | 28 | 30 | 36 | 31 | 20 | 11 | 11 | 15 | 20 | 25 | 30 |
| Rain days | 9 | 8 | 9 | 11 | 10 | 6 | 3 | 4 | 4 | 7 | 7 | 9 |
| Rain on a day (%) | Rain days | |
|---|---|---|
| Jan | 30 | 9 |
| Feb | 28 | 8 |
| Mar | 30 | 9 |
| Apr | 36 | 11 |
| May | 31 | 10 |
| Jun | 20 | 6 |
| Jul | 11 | 3 |
| Aug | 11 | 4 |
| Sep | 15 | 4 |
| Oct | 20 | 7 |
| Nov | 25 | 7 |
| Dec | 30 | 9 |
Monthly rainfall
Over a full year, Idaho Falls collects about 15.0 in of rain across 88 wet days — roughly 1.3 in in an average month.
It doesn’t fall evenly. May is the wettest month with 2.1 in, while July is the driest at just 0.5 in. The three wettest months alone bring about 36% 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) | 1.4 | 1.1 | 1.4 | 1.8 | 2.1 | 1.2 | 0.5 | 0.5 | 1.0 | 1.3 | 1.2 | 1.5 |
| Rain days | 9 | 8 | 9 | 11 | 10 | 6 | 3 | 4 | 4 | 7 | 7 | 9 |
| Snow days | 10 | 7 | 5 | 3 | 1 | 0 | 0 | 0 | 0 | 1 | 6 | 10 |
| Rainfall (in) | Rain days | Snow days | |
|---|---|---|---|
| Jan | 1.4 | 9 | 10 |
| Feb | 1.1 | 8 | 7 |
| Mar | 1.4 | 9 | 5 |
| Apr | 1.8 | 11 | 3 |
| May | 2.1 | 10 | 1 |
| Jun | 1.2 | 6 | 0 |
| Jul | 0.5 | 3 | 0 |
| Aug | 0.5 | 4 | 0 |
| Sep | 1.0 | 4 | 0 |
| Oct | 1.3 | 7 | 1 |
| Nov | 1.2 | 7 | 6 |
| Dec | 1.5 | 9 | 10 |
Snow in Idaho Falls
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.
Idaho Falls averages about 43 snowy days a year. Snow season runs roughly Sep 30 to May 21 — about 7.7 months.
January is snowiest, with roughly 10 days of snow and an estimated 15 in of snowfall. Over the year that adds up to an estimated 59 in of snow.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Snow days | 10 | 7 | 5 | 3 | 1 | 0 | 0 | 0 | 0 | 1 | 6 | 10 |
| Snowfall (in) | 15 | 11 | 5 | 4 | 1 | 0 | 0 | 0 | 0 | 1 | 8 | 14 |
| Snow days | Snowfall (in) | |
|---|---|---|
| Jan | 10 | 15 |
| Feb | 7 | 11 |
| Mar | 5 | 5 |
| Apr | 3 | 4 |
| May | 1 | 1 |
| Jun | 0 | 0 |
| Jul | 0 | 0 |
| Aug | 0 | 0 |
| Sep | 0 | 0 |
| Oct | 1 | 1 |
| Nov | 6 | 8 |
| Dec | 10 | 14 |
Clouds and sunshine
How often the daytime sky is clear, partly cloudy or overcast.
In Idaho Falls, 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 June 7 and lasts for 4.8 months, ending around October 31. The clearest month is August, when the sky is clear, mostly clear, or partly cloudy 83% of the time on average.
The cloudier part of the year begins around November 1 and lasts for 7.2 months, ending around June 6. The cloudiest month is January, when it is overcast or mostly cloudy 63% of the time.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 37 | 41 | 40 | 39 | 46 | 64 | 83 | 83 | 73 | 63 | 46 | 37 |
| Cloudier (%) | 63 | 59 | 60 | 61 | 54 | 36 | 17 | 17 | 27 | 37 | 54 | 63 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| Jan | 37 | 63 |
| Feb | 41 | 59 |
| Mar | 40 | 60 |
| Apr | 39 | 61 |
| May | 46 | 54 |
| Jun | 64 | 36 |
| Jul | 83 | 17 |
| Aug | 83 | 17 |
| Sep | 73 | 27 |
| Oct | 63 | 37 |
| Nov | 46 | 54 |
| Dec | 37 | 63 |
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 11, brings about 15 h 12 min of light; the shortest, around January 1, only 8 h 48 min — a swing of roughly 6 h 24 min.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 9.1 | 10.2 | 11.6 | 13.2 | 14.5 | 15.2 | 14.9 | 13.8 | 12.3 | 10.8 | 9.5 | 8.8 |
| Sunrise (AM) | 8:04 | 7:36 | 6:49 | 5:53 | 5:09 | 4:52 | 5:06 | 5:38 | 6:14 | 6:50 | 7:30 | 8:01 |
| Sunset (PM) | 5:11 | 5:49 | 6:27 | 7:04 | 7:39 | 8:05 | 8:02 | 7:26 | 6:31 | 5:37 | 4:57 | 4:48 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| Jan | 9.1 | 8:04 | 5:11 |
| Feb | 10.2 | 7:36 | 5:49 |
| Mar | 11.6 | 6:49 | 6:27 |
| Apr | 13.2 | 5:53 | 7:04 |
| May | 14.5 | 5:09 | 7:39 |
| Jun | 15.2 | 4:52 | 8:05 |
| Jul | 14.9 | 5:06 | 8:02 |
| Aug | 13.8 | 5:38 | 7:26 |
| Sep | 12.3 | 6:14 | 6:31 |
| Oct | 10.8 | 6:50 | 5:37 |
| Nov | 9.5 | 7:30 | 4:57 |
| Dec | 8.8 | 8:01 | 4:48 |
Sunny days
How many genuinely sunny days each month brings — days the sky stays clear or mostly clear — banded into plain-language zones.
Idaho Falls averages about 11 sunny days a month — counting the days the sky stays clear or mostly clear — with a clear seasonal swing between 5 and 20 days.
The sunnier stretch runs 4.7 months, from around Jun 10 to Oct 31. The sunniest month is July, with roughly 20 sunny days (bright).
The greyest month is April, down near 6 sunny days — about 69% fewer than the July peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sunny days | 8 | 8 | 7 | 6 | 8 | 14 | 20 | 20 | 17 | 14 | 9 | 7 |
| Sky | Gloomy | Mixed | Gloomy | Gloomy | Gloomy | Mixed | Bright | Bright | Bright | Mixed | Mixed | Gloomy |
| Sunny days | Sky | |
|---|---|---|
| Jan | 8 | Gloomy |
| Feb | 8 | Mixed |
| Mar | 7 | Gloomy |
| Apr | 6 | Gloomy |
| May | 8 | Gloomy |
| Jun | 14 | Mixed |
| Jul | 20 | Bright |
| Aug | 20 | Bright |
| Sep | 17 | Bright |
| Oct | 14 | Mixed |
| Nov | 9 | Mixed |
| Dec | 7 | Gloomy |
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 Idaho Falls, the air stays dry or comfortable essentially all year. Even in July, the muggiest month, it feels humid or worse only about 0% 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 | 100 | 99 | 99 | 100 | 100 | 100 | 100 |
| Comfortable (%) | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 |
| Dry (%) | Comfortable (%) | |
|---|---|---|
| Jan | 100 | 0 |
| Feb | 100 | 0 |
| Mar | 100 | 0 |
| Apr | 100 | 0 |
| May | 100 | 0 |
| Jun | 100 | 0 |
| Jul | 99 | 1 |
| Aug | 99 | 1 |
| Sep | 100 | 0 |
| Oct | 100 | 0 |
| Nov | 100 | 0 |
| Dec | 100 | 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 Idaho Falls is steady company: average speeds sit near 6 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) | 6 | 6 | 7 | 7 | 7 | 7 | 6 | 6 | 6 | 6 | 6 | 6 |
| Feels | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm |
| Wind speed (mph) | Feels | |
|---|---|---|
| Jan | 6 | calm |
| Feb | 6 | calm |
| Mar | 7 | calm |
| Apr | 7 | calm |
| May | 7 | calm |
| Jun | 7 | calm |
| Jul | 6 | calm |
| Aug | 6 | calm |
| Sep | 6 | calm |
| Oct | 6 | calm |
| Nov | 6 | calm |
| Dec | 6 | calm |
Best time to visit Idaho Falls
To characterize how pleasant the weather is in Idaho Falls throughout the year, we compute two travel scores — one for general sightseeing, one for beach and pool weather.
Around late September, Idaho Falls is still near the tail of its best-weather window — great conditions with the peak-season crowds already thinning.
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 Idaho Falls for general outdoor tourist activities run from late May to early July and again from mid August to early October, with a peak score in the second week of September.
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) | 0.0 | 0.0 | 1.6 | 3.8 | 6.1 | 7.4 | 5.9 | 6.5 | 7.9 | 5.0 | 0.8 | 0.0 |
| Rating | poor | poor | poor | fair | good | good | good | good | ideal | fair | poor | poor |
| Travel score (0–10) | Rating | |
|---|---|---|
| Jan | 0.0 | poor |
| Feb | 0.0 | poor |
| Mar | 1.6 | poor |
| Apr | 3.8 | fair |
| May | 6.1 | good |
| Jun | 7.4 | good |
| Jul | 5.9 | good |
| Aug | 6.5 | good |
| Sep | 7.9 | ideal |
| Oct | 5.0 | fair |
| Nov | 0.8 | poor |
| Dec | 0.0 | poor |
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 Idaho Falls for hot-weather activities is from mid June to mid September, with a peak score in the third week of August.
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 Idaho Falls, 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 July (highs near 87°F), the essentials are light clothes and sun protection. In the cold season around January (highs near 31°F), pack a warm layer, a heavy coat and rain gear.
In July, Idaho Falls sees daytime highs around 87°F and nights near 57°F. Pack light clothes and sun protection. About 3 days see rain.
UV index (midday) in Idaho Falls 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 Idaho Falls peaks around July 12 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near January 1 at about 2 (low).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 2 | 3 | 5 | 5 | 8 | 9 | 9 | 8 | 6 | 4 | 2 | 2 |
| Level | Low | Moderate | Moderate | Moderate | Very high | Very high | Very high | Very high | High | Moderate | Low | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 2 | Low |
| Feb | 3 | Moderate |
| Mar | 5 | Moderate |
| Apr | 5 | Moderate |
| May | 8 | Very high |
| Jun | 9 | Very high |
| Jul | 9 | Very high |
| Aug | 8 | Very high |
| Sep | 6 | High |
| Oct | 4 | Moderate |
| Nov | 2 | Low |
| Dec | 2 | Low |
Average hourly UV index in Idaho Falls
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 July the burn window is concentrated in the middle of the day: about 8.5 hours a day reach index 3 (protection recommended), and 5 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) | 0 | 0 | 4.5 | 5.5 | 7.5 | 8.5 | 8.5 | 7.5 | 6 | 4 | 0 | 0 |
| UV ≥ 6 (h/day) | 0 | 0 | 0 | 0 | 4 | 5 | 5 | 4 | 0 | 0 | 0 | 0 |
| UV ≥ 3 (h/day) | UV ≥ 6 (h/day) | |
|---|---|---|
| Jan | 0 | 0 |
| Feb | 0 | 0 |
| Mar | 4.5 | 0 |
| Apr | 5.5 | 0 |
| May | 7.5 | 4 |
| Jun | 8.5 | 5 |
| Jul | 8.5 | 5 |
| Aug | 7.5 | 4 |
| Sep | 6 | 0 |
| Oct | 4 | 0 |
| Nov | 0 | 0 |
| Dec | 0 | 0 |
Air quality in Idaho Falls 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 Idaho Falls is worst in August — around 20 µg/m³ PM2.5 (moderate), about 3.1× the cleanest month (December, 7 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) | 8 | 9 | 10 | 10 | 10 | 9 | 17 | 20 | 14 | 9 | 9 | 7 |
| Level | Good | Good | Good | Good | Good | Good | Moderate | Moderate | Moderate | Good | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 8 | Good |
| Feb | 9 | Good |
| Mar | 10 | Good |
| Apr | 10 | Good |
| May | 10 | Good |
| Jun | 9 | Good |
| Jul | 17 | Moderate |
| Aug | 20 | Moderate |
| Sep | 14 | Moderate |
| Oct | 9 | Good |
| Nov | 9 | Good |
| Dec | 7 | Good |
Growing season
The growing season in Idaho Falls typically lasts about 207 days, from around April 4 to October 27 — the span where a frost-free day is more likely than not. It is reliably frost-free from May 12 to October 1.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Frost-free chance (%) | 8 | 13 | 32 | 64 | 92 | 100 | 100 | 100 | 98 | 70 | 24 | 9 |
| Frost nights | 31 | 28 | 31 | 30 | 11 | 0 | 0 | 0 | 0 | 31 | 30 | 31 |
| Frost-free chance (%) | Frost nights | |
|---|---|---|
| Jan | 8 | 31 |
| Feb | 13 | 28 |
| Mar | 32 | 31 |
| Apr | 64 | 30 |
| May | 92 | 11 |
| Jun | 100 | 0 |
| Jul | 100 | 0 |
| Aug | 100 | 0 |
| Sep | 98 | 0 |
| Oct | 70 | 31 |
| Nov | 24 | 30 |
| Dec | 9 | 31 |
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. Idaho Falls banks about 2,153 degree days a year, and the running total — which growers use to time plantings and predict maturity — climbs fastest around July.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Growing degree days (°F·days) | 0 | 0 | 0 | 0 | 132 | 389 | 676 | 626 | 310 | 20 | 0 | 0 |
| Growing degree days (°F·days) | |
|---|---|
| Jan | 0 |
| Feb | 0 |
| Mar | 0 |
| Apr | 0 |
| May | 132 |
| Jun | 389 |
| Jul | 676 |
| Aug | 626 |
| Sep | 310 |
| Oct | 20 |
| Nov | 0 |
| 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.
Idaho Falls receives about 4.8 kWh/m² a day of solar energy on average — bright — with a clear seasonal swing between 1.7 and 8.1 kWh/m².
The brighter stretch of the year lasts 6.1 months, from around Mar 23 to Sep 24. The brightest month is July, averaging about 7.9 kWh/m² (intense).
The dimmest month is December, down near 1.7 kWh/m² — roughly 78% less than the July peak.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 2.0 | 3.1 | 4.6 | 5.9 | 6.9 | 7.7 | 7.9 | 7.0 | 5.4 | 3.6 | 2.3 | 1.7 |
| Level | Moderate | Moderate | Bright | Bright | Intense | Intense | Intense | Intense | Bright | Moderate | Moderate | Dim |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| Jan | 2.0 | Moderate |
| Feb | 3.1 | Moderate |
| Mar | 4.6 | Bright |
| Apr | 5.9 | Bright |
| May | 6.9 | Intense |
| Jun | 7.7 | Intense |
| Jul | 7.9 | Intense |
| Aug | 7.0 | Intense |
| Sep | 5.4 | Bright |
| Oct | 3.6 | Moderate |
| Nov | 2.3 | Moderate |
| Dec | 1.7 | Dim |
Where is Idaho Falls?
Idaho Falls sits at 43.5°N, 112.0°W, 4,705 ft above sea level, in United States. The nearest listed city is Rexburg, 28 mi away.
Topography around Idaho Falls
How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Idaho Falls.
Within 2 miles, the terrain around Idaho Falls has only modest variations in elevation — a maximum elevation change of 95 ft around an average of 4,698 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 1,693 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 5,561 ft.
The land around Idaho Falls is covered by artificial surfaces (33%) and trees (22%) within 2 miles, cropland (45%) and grassland (38%) within 10 miles, and grassland (54%) and cropland (22%) 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 Idaho Falls (43.4666°, -112.0341°, elevation 4,705 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).