Highland weather in September

In September, Highland sees average daytime highs of 85°F and overnight lows near 61°F, with 0.3 in of rain across 1.6 wet days and about 12.2 hours of daylight. It is the 3rd-warmest and 11th-wettest month of the year here.

Highs ease over the month, from about 88°F in the first days to 81°F by the end. The sky is clear or mostly clear about 88% of the time in September, and the air most often feels dry.

Daylight stretches from about 12 h 42 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is Highland's 1st-clearest and 12th-windiest month. For the whole year in context, see Highland's year-round climate.

Daytime high: 85°; 3rd warmest
Overnight low: 61°; 10th coldest
Rainfall: 0.3 in; 1.6 wet days
Daylight: 12 h 12 min; 5:37 AM – 5:49 PM
Cloud cover: 15%; 1st clearest
Wind: 3 mph; 12th windiest
Solar energy: 6.3 kWh/m²
Travel score: 7.2; out of 10

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.

← August Highland year-round climate October →Best places to visit in September

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 88°F in the first days to 81°F by the end.

A typical September day in Highland reaches about 85°F in the afternoon and slips back to 61°F overnight — a 24°F spread between the day's warmth and the night's chill. On most days the high lands between 75°F and 93°F. Set against its neighbours, September runs about 5°F cooler than August and about 10°F warmer than October.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Avg high (°F)	88	88	88	88	87	87	87	87	86	86	86	85	85	85	85	84	84	84	84	83	83	83	83	83	82	82	82	81	81	81
Avg low (°F)	65	64	64	64	64	64	63	63	63	62	62	62	62	61	61	61	60	60	60	60	60	59	59	59	59	58	58	58	58	57

	Avg high (°F)	Avg low (°F)
1	88	65
2	88	64
3	88	64
4	88	64
5	87	64
6	87	64
7	87	63
8	87	63
9	86	63
10	86	62
11	86	62
12	85	62
13	85	62
14	85	61
15	85	61
16	84	61
17	84	60
18	84	60
19	84	60
20	83	60
21	83	60
22	83	59
23	83	59
24	83	59
25	82	59
26	82	58
27	82	58
28	81	58
29	81	58
30	81	57

How September really feels in Highland

Once humidity and wind are folded in, September averages 0 days that feel above 90°F and 0 that feel at or below 32°F — the comfort signal a plain temperature reading hides.

Days feeling ≥ 90°F

heat index over the day's high

Days feeling ≤ 32°F

wind chill below the day's low

September sits comfortably in between — no days that feel dangerously hot or drop to a hard freeze once humidity and wind are folded in.

Highland weather by month

How September compares with the rest of the year at a glance. September is the 3rd-warmest and 11th-wettest month here — the current month is highlighted below.

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

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 88% of the time in September, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 6% of September, with mostly cloudy or overcast conditions the remaining 7%.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Clearer (%)	93	94	94	94	94	94	94	94	94	95	94	94	94	94	94	94	94	93	93	93	93	93	93	93	93	93	93	92	92	92
Cloudier (%)	7	6	6	6	6	6	6	6	6	5	6	6	6	6	6	6	6	7	7	7	7	7	7	7	7	7	7	8	8	8

	Clearer (%)	Cloudier (%)
1	93	7
2	94	6
3	94	6
4	94	6
5	94	6
6	94	6
7	94	6
8	94	6
9	94	6
10	95	5
11	94	6
12	94	6
13	94	6
14	94	6
15	94	6
16	94	6
17	94	6
18	93	7
19	93	7
20	93	7
21	93	7
22	93	7
23	93	7
24	93	7
25	93	7
26	93	7
27	93	7
28	92	8
29	92	8
30	92	8

Chance of precipitation in September

Any precipitation

Highland gets around 0.3 in of rain over 1.6 wet days in September. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 5% and peaks near 10% on the wettest days.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Rain chance (%)	10	9	9	9	9	8	8	7	6	6	5	5	4	4	4	3	3	3	3	3	3	3	3	4	4	4	4	4	5	5

	Rain chance (%)
1	10
2	9
3	9
4	9
5	9
6	8
7	8
8	7
9	6
10	6
11	5
12	5
13	4
14	4
15	4
16	3
17	3
18	3
19	3
20	3
21	3
22	3
23	3
24	4
25	4
26	4
27	4
28	4
29	5
30	5

Humidity in September

DryComfortableHumidMuggyOppressiveMiserable

Most of September feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.

By dew point, September lands in the dry band about 90% of days. It rarely turns muggy — the humid and sticky bands barely register.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Dry (%)	82	82	83	83	84	84	85	86	87	88	89	91	91	92	92	93	93	93	93	93	94	94	94	94	95	95	95	96	96	96
Comfortable (%)	14	14	14	14	13	13	12	12	11	10	9	8	8	7	7	6	6	6	6	6	5	5	5	5	5	5	5	4	4	4
Humid (%)	4	4	3	3	3	3	3	2	2	2	2	1	1	1	1	1	1	1	1	1	1	1	1	1	0	0	0	0	0	0

	Dry (%)	Comfortable (%)	Humid (%)
1	82	14	4
2	82	14	4
3	83	14	3
4	83	14	3
5	84	13	3
6	84	13	3
7	85	12	3
8	86	12	2
9	87	11	2
10	88	10	2
11	89	9	2
12	91	8	1
13	91	8	1
14	92	7	1
15	92	7	1
16	93	6	1
17	93	6	1
18	93	6	1
19	93	6	1
20	93	6	1
21	94	5	1
22	94	5	1
23	94	5	1
24	94	5	1
25	95	5	0
26	95	5	0
27	95	5	0
28	96	4	0
29	96	4	0
30	96	4	0

Wind in September

Winds average 3 mph in September, the calmest month.

Across September, daily wind ranges from about 3 mph on the calmest days to 4 mph at its breeziest. It stays fairly steady from day to day.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Wind speed (mph)	3	3	3	3	3	3	3	3	3	3	3	3	3	3	3	3	3	3	3	3	3	3	4	4	4	4	4	4	4	4
Feels	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm	calm

	Wind speed (mph)	Feels
1	3	calm
2	3	calm
3	3	calm
4	3	calm
5	3	calm
6	3	calm
7	3	calm
8	3	calm
9	3	calm
10	3	calm
11	3	calm
12	3	calm
13	3	calm
14	3	calm
15	3	calm
16	3	calm
17	3	calm
18	3	calm
19	3	calm
20	3	calm
21	3	calm
22	3	calm
23	4	calm
24	4	calm
25	4	calm
26	4	calm
27	4	calm
28	4	calm
29	4	calm
30	4	calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 42 min at the start of September to 11 h 42 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 60 minutes over September. Sunrise moves from 5:26 AM to 5:47 AM, and sunset from 6:11 PM to 5:29 PM.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Daylight (h)	12.7	12.7	12.7	12.6	12.6	12.6	12.5	12.5	12.5	12.4	12.4	12.4	12.3	12.3	12.2	12.2	12.2	12.1	12.1	12.1	12.0	12.0	12.0	11.9	11.9	11.8	11.8	11.8	11.7	11.7
Sunrise (AM)	5:26	5:27	5:28	5:28	5:29	5:30	5:30	5:31	5:32	5:33	5:33	5:34	5:35	5:35	5:36	5:37	5:38	5:38	5:39	5:40	5:40	5:41	5:42	5:43	5:43	5:44	5:45	5:46	5:46	5:47
Sunset (PM)	6:11	6:10	6:08	6:07	6:05	6:04	6:03	6:01	6:00	5:58	5:57	5:55	5:54	5:52	5:51	5:49	5:48	5:47	5:45	5:44	5:42	5:41	5:39	5:38	5:36	5:35	5:33	5:32	5:31	5:29

	Daylight (h)	Sunrise (AM)	Sunset (PM)
1	12.7	5:26	6:11
2	12.7	5:27	6:10
3	12.7	5:28	6:08
4	12.6	5:28	6:07
5	12.6	5:29	6:05
6	12.6	5:30	6:04
7	12.5	5:30	6:03
8	12.5	5:31	6:01
9	12.5	5:32	6:00
10	12.4	5:33	5:58
11	12.4	5:33	5:57
12	12.4	5:34	5:55
13	12.3	5:35	5:54
14	12.3	5:35	5:52
15	12.2	5:36	5:51
16	12.2	5:37	5:49
17	12.2	5:38	5:48
18	12.1	5:38	5:47
19	12.1	5:39	5:45
20	12.1	5:40	5:44
21	12.0	5:40	5:42
22	12.0	5:41	5:41
23	12.0	5:42	5:39
24	11.9	5:43	5:38
25	11.9	5:43	5:36
26	11.8	5:44	5:35
27	11.8	5:45	5:33
28	11.8	5:46	5:32
29	11.7	5:46	5:31
30	11.7	5:47	5:29

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 6.3 kWh/m².

For context, solar energy here swings from a low near 3.04 kWh/m² to a high of 8.39 kWh/m² in June across the year — September's 6.3 kWh/m² falls in the middle.

	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30
Solar energy (kWh/m²)	6.8	6.8	6.7	6.7	6.7	6.6	6.6	6.6	6.5	6.5	6.5	6.5	6.4	6.4	6.4	6.3	6.3	6.3	6.2	6.2	6.1	6.1	6.0	6.0	6.0	5.9	5.9	5.8	5.8	5.7
Level	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Intense	Bright	Bright	Bright	Bright	Bright	Bright

	Solar energy (kWh/m²)	Level
1	6.8	Intense
2	6.8	Intense
3	6.7	Intense
4	6.7	Intense
5	6.7	Intense
6	6.6	Intense
7	6.6	Intense
8	6.6	Intense
9	6.5	Intense
10	6.5	Intense
11	6.5	Intense
12	6.5	Intense
13	6.4	Intense
14	6.4	Intense
15	6.4	Intense
16	6.3	Intense
17	6.3	Intense
18	6.3	Intense
19	6.2	Intense
20	6.2	Intense
21	6.1	Intense
22	6.1	Intense
23	6.0	Intense
24	6.0	Intense
25	6.0	Bright
26	5.9	Bright
27	5.9	Bright
28	5.8	Bright
29	5.8	Bright
30	5.7	Bright

Planning a trip in September

Is September a good time to visit Highland?

Our two travel scores rate September for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).

7.2

Sightseeing

5th-best month of the year

8.9

Beach & pool

1st-best month of the year

September is one of the better times to visit Highland for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Highland in September

From September's temperature range, rain chance, sun and wind — what's worth putting in the bag.

In September, Highland sees daytime highs around 85°F and nights near 61°F. Pack light clothes and sun protection.

light clothessun protection

UV index in Highland in September

LowModerateHighVery highExtreme

Clear-sky midday UV in September peaks around 8 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

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

Air quality in Highland in September

GoodModeratePoorUnhealthyVery unhealthy

Average fine-particle pollution (PM2.5) through the year — so you can see where September falls, not just the annual 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

Location & terrain

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.

2 miles

1,558 ft

artificial surfaces 57%

10 miles

6,699 ft

trees 28%

50 miles

11,411 ft

shrubs 29%

treesshrubsgrasslandcroplandartificial surfacesbare terrainwater

← August Highland year-round climate October →Best places to visit in September

September weather nearby: San Bernardino 5.0 mi · Redlands 5.0 mi · Loma Linda 6.2 mi · Colton 6.8 mi · Rialto 9.3 mi · Bloomington 11 mi · Yucaipa 12 mi · Fontana 13 mi

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).

	Avg high (°F)	Avg low (°F)
1	88	65
2	88	64
3	88	64
4	88	64
5	87	64
6	87	64
7	87	63
8	87	63
9	86	63
10	86	62
11	86	62
12	85	62
13	85	62
14	85	61
15	85	61
16	84	61
17	84	60
18	84	60
19	84	60
20	83	60
21	83	60
22	83	59
23	83	59
24	83	59
25	82	59
26	82	58
27	82	58
28	81	58
29	81	58
30	81	57

	Clearer (%)	Cloudier (%)
1	93	7
2	94	6
3	94	6
4	94	6
5	94	6
6	94	6
7	94	6
8	94	6
9	94	6
10	95	5
11	94	6
12	94	6
13	94	6
14	94	6
15	94	6
16	94	6
17	94	6
18	93	7
19	93	7
20	93	7
21	93	7
22	93	7
23	93	7
24	93	7
25	93	7
26	93	7
27	93	7
28	92	8
29	92	8
30	92	8

	Rain chance (%)
1	10
2	9
3	9
4	9
5	9
6	8
7	8
8	7
9	6
10	6
11	5
12	5
13	4
14	4
15	4
16	3
17	3
18	3
19	3
20	3
21	3
22	3
23	3
24	4
25	4
26	4
27	4
28	4
29	5
30	5

	Dry (%)	Comfortable (%)	Humid (%)
1	82	14	4
2	82	14	4
3	83	14	3
4	83	14	3
5	84	13	3
6	84	13	3
7	85	12	3
8	86	12	2
9	87	11	2
10	88	10	2
11	89	9	2
12	91	8	1
13	91	8	1
14	92	7	1
15	92	7	1
16	93	6	1
17	93	6	1
18	93	6	1
19	93	6	1
20	93	6	1
21	94	5	1
22	94	5	1
23	94	5	1
24	94	5	1
25	95	5	0
26	95	5	0
27	95	5	0
28	96	4	0
29	96	4	0
30	96	4	0

	Avg high (°F)	Avg low (°F)
1	88	65
2	88	64
3	88	64
4	88	64
5	87	64
6	87	64
7	87	63
8	87	63
9	86	63
10	86	62
11	86	62
12	85	62
13	85	62
14	85	61
15	85	61
16	84	61
17	84	60
18	84	60
19	84	60
20	83	60
21	83	60
22	83	59
23	83	59
24	83	59
25	82	59
26	82	58
27	82	58
28	81	58
29	81	58
30	81	57

	Clearer (%)	Cloudier (%)
1	93	7
2	94	6
3	94	6
4	94	6
5	94	6
6	94	6
7	94	6
8	94	6
9	94	6
10	95	5
11	94	6
12	94	6
13	94	6
14	94	6
15	94	6
16	94	6
17	94	6
18	93	7
19	93	7
20	93	7
21	93	7
22	93	7
23	93	7
24	93	7
25	93	7
26	93	7
27	93	7
28	92	8
29	92	8
30	92	8

	Rain chance (%)
1	10
2	9
3	9
4	9
5	9
6	8
7	8
8	7
9	6
10	6
11	5
12	5
13	4
14	4
15	4
16	3
17	3
18	3
19	3
20	3
21	3
22	3
23	3
24	4
25	4
26	4
27	4
28	4
29	5
30	5

	Dry (%)	Comfortable (%)	Humid (%)
1	82	14	4
2	82	14	4
3	83	14	3
4	83	14	3
5	84	13	3
6	84	13	3
7	85	12	3
8	86	12	2
9	87	11	2
10	88	10	2
11	89	9	2
12	91	8	1
13	91	8	1
14	92	7	1
15	92	7	1
16	93	6	1
17	93	6	1
18	93	6	1
19	93	6	1
20	93	6	1
21	94	5	1
22	94	5	1
23	94	5	1
24	94	5	1
25	95	5	0
26	95	5	0
27	95	5	0
28	96	4	0
29	96	4	0
30	96	4	0

	Avg high (°F)	Avg low (°F)
1	88	65
2	88	64
3	88	64
4	88	64
5	87	64
6	87	64
7	87	63
8	87	63
9	86	63
10	86	62
11	86	62
12	85	62
13	85	62
14	85	61
15	85	61
16	84	61
17	84	60
18	84	60
19	84	60
20	83	60
21	83	60
22	83	59
23	83	59
24	83	59
25	82	59
26	82	58
27	82	58
28	81	58
29	81	58
30	81	57

	Clearer (%)	Cloudier (%)
1	93	7
2	94	6
3	94	6
4	94	6
5	94	6
6	94	6
7	94	6
8	94	6
9	94	6
10	95	5
11	94	6
12	94	6
13	94	6
14	94	6
15	94	6
16	94	6
17	94	6
18	93	7
19	93	7
20	93	7
21	93	7
22	93	7
23	93	7
24	93	7
25	93	7
26	93	7
27	93	7
28	92	8
29	92	8
30	92	8

	Rain chance (%)
1	10
2	9
3	9
4	9
5	9
6	8
7	8
8	7
9	6
10	6
11	5
12	5
13	4
14	4
15	4
16	3
17	3
18	3
19	3
20	3
21	3
22	3
23	3
24	4
25	4
26	4
27	4
28	4
29	5
30	5

	Dry (%)	Comfortable (%)	Humid (%)
1	82	14	4
2	82	14	4
3	83	14	3
4	83	14	3
5	84	13	3
6	84	13	3
7	85	12	3
8	86	12	2
9	87	11	2
10	88	10	2
11	89	9	2
12	91	8	1
13	91	8	1
14	92	7	1
15	92	7	1
16	93	6	1
17	93	6	1
18	93	6	1
19	93	6	1
20	93	6	1
21	94	5	1
22	94	5	1
23	94	5	1
24	94	5	1
25	95	5	0
26	95	5	0
27	95	5	0
28	96	4	0
29	96	4	0
30	96	4	0