Barstow weather in September

In September, Barstow sees average daytime highs of 90°F and overnight lows near 64°F, with 0.1 in of rain across 0.6 wet days and about 12.2 hours of daylight. It is the 4th-warmest and 9th-wettest month of the year here.

Highs ease over the month, from about 94°F in the first days to 86°F by the end. The sky is clear or mostly clear about 87% of the time in September, and the air most often feels dry.

Daylight stretches from about 12 h 48 min at the start of September to 11 h 42 min by month's end. Set against the rest of the year, September is Barstow's 1st-clearest and 8th-windiest month. For the whole year in context, see Barstow's year-round climate.

Daytime high
90°
4th warmest
Overnight low
64°
9th coldest
Rainfall
0.1 in
0.6 wet days
Daylight
12 h 12 min
5:36 AM – 5:49 PM
Cloud cover
13%
1st clearest
Wind
6 mph
8th windiest
Solar energy
6.46 kWh/m²
Travel score
5.2
out of 10

Barstow is city in San Bernardino County, California, United States.

Density
221/km²
people per km²
Founded
1947

Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.

Temperature in September

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 94°F in the first days to 86°F by the end.

A typical September day in Barstow reaches about 90°F in the afternoon and slips back to 64°F overnight — a 26°F spread between the day's warmth and the night's chill. On most days the high lands between 81°F and 97°F. Set against its neighbours, September runs about 7°F cooler than August and about 12°F warmer than October.

60°80°100°151015202530
Avg high (°F)Avg low (°F)
19569
29569
39469
49468
59468
69368
79367
89367
99267
109266
119266
129165
139165
149165
159065
169064
179064
188964
198963
208963
218963
228862
238862
248762
258761
268761
278661
288660
298660
308559

How September really feels in Barstow

Once humidity and wind are folded in, September averages 17 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
17
heat index over the day's high
Days feeling ≤ 32°F
0
wind chill below the day's low

The story in September is heat — humidity pushes the afternoon "feels like" well above the raw temperature.

Barstow weather by month

How September compares with the rest of the year at a glance. September is the 4th-warmest and 9th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysDaylight (hours)Travel score
Jan58° / 38°0.73.39.95.2
Feb62° / 41°0.93.710.76.3
Mar68° / 46°0.52.511.77.8
Apr74° / 50°0.31.512.98.7
May83° / 57°0.10.313.87.8
Jun92° / 65°0.00.214.34.4
Jul98° / 72°0.21.114.12.2
Aug97° / 71°0.10.613.32.5
Sep90° / 64°0.10.612.25.2
Oct78° / 54°0.21.111.18.7
Nov65° / 43°0.31.410.27.6
Dec57° / 37°0.62.59.74.9

Cloud cover in September

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 87% of the time in September, the clearest month of the year.

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

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
1946
2946
3946
4946
5946
6946
7946
8946
9946
10946
11946
12955
13955
14955
15955
16955
17946
18937
19937
20937
21937
22937
23937
24937
25937
26937
27937
28937
29937
30937

Chance of precipitation in September

Any precipitation

Barstow gets around 0.1 in of rain over 0.6 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 2% and peaks near 3% on the wettest days.

0%10%20%30%151015202530
Rain chance (%)
13
23
33
43
53
63
73
83
93
103
112
122
132
142
152
162
172
182
192
201
211
221
231
241
251
262
272
282
292
302

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 96% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)
19352
29352
39352
49352
59442
69442
79442
89442
99442
109532
119631
129631
139721
149721
159721
169721
179811
189910
199910
209910
219910
229910
239910
249910
259910
269910
279910
289910
299910
309910

Wind in September

Winds average 6 mph in September.

Across September, daily wind ranges from about 6 mph on the calmest days to 7 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202530
Wind speed (mph)Feels
17calm
27calm
37calm
47calm
57calm
67calm
77calm
87calm
97calm
107calm
117calm
127calm
137calm
147calm
157calm
167calm
177calm
187calm
197calm
206calm
216calm
226calm
236calm
246calm
256calm
266calm
276calm
286calm
296calm
306calm

Sunrise & sunset in September

DaylightNight

Daylight runs from about 12 h 48 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 66 minutes over September. Sunrise moves from 5:25 AM to 5:47 AM, and sunset from 6:11 PM to 5:28 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.85:256:11
212.75:256:09
312.75:266:08
412.75:276:07
512.65:286:05
612.65:286:04
712.65:296:02
812.55:306:01
912.55:315:59
1012.45:315:58
1112.45:325:56
1212.45:335:55
1312.35:345:53
1412.35:345:52
1512.35:355:50
1612.25:365:49
1712.25:375:47
1812.15:375:46
1912.15:385:44
2012.15:395:43
2112.05:405:41
2212.05:405:40
2312.05:415:38
2411.95:425:37
2511.95:435:35
2611.85:445:34
2711.85:445:33
2811.85:455:31
2911.75:465:30
3011.75:475:28

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 6.46 kWh/m².

For context, solar energy here swings from a low near 3.12 kWh/m² to a high of 8.65 kWh/m² in June across the year — September's 6.46 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
17.0Intense
26.9Intense
36.9Intense
46.8Intense
56.8Intense
66.8Intense
76.8Intense
86.7Intense
96.7Intense
106.7Intense
116.6Intense
126.6Intense
136.6Intense
146.5Intense
156.5Intense
166.5Intense
176.4Intense
186.4Intense
196.4Intense
206.3Intense
216.3Intense
226.2Intense
236.2Intense
246.1Intense
256.1Intense
266.0Intense
276.0Intense
286.0Bright
295.9Bright
305.9Bright
Planning a trip in September

Is September a good time to visit Barstow?

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

5.2
Sightseeing
7th-best month of the year
8.4
Beach & pool
2nd-best month of the year

September is a reasonable time to visit Barstow for sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Barstow in September

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

In September, Barstow sees daytime highs around 90°F and nights near 64°F. Pack light clothes and sun protection.

light clothessun protection

UV index in Barstow 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 Barstow peaks around June 23 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 17 at about 3 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 11 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highHighModerateJun 23UV 11Dec 17UV 3
UV index (midday)Level
Jan3Moderate
Feb5Moderate
Mar5High
Apr8Very high
May8Very high
Jun11Extreme
Jul11Extreme
Aug11Extreme
Sep8Very high
Oct6High
Nov3Moderate
Dec3Moderate
Location & terrain

Where is Barstow?

Barstow sits at 34.9°N, 117.0°W, 2,175 ft above sea level, in United States. The nearest listed city is Barstow Heights, 2.5 mi away.

Topography around Barstow

How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Barstow.

Within 2 miles, the terrain around Barstow has only modest variations in elevation — a maximum elevation change of 525 ft around an average of 2,211 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 2,096 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 8,891 ft.

The land around Barstow is covered by bare terrain (55%) and artificial surfaces (35%) within 2 miles, bare terrain (91%) within 10 miles, and bare terrain (69%) within 50 miles.

2 miles
525 ft
10 miles
2,096 ft
50 miles
8,891 ft
treesshrubsgrasslandcroplandartificial surfacesbare terrain
September weather nearby: Barstow Heights 2.5 mi · Apple Valley 29 mi · Victorville 29 mi · Adelanto 31 mi · Hesperia 36 mi · Highland 54 mi · San Bernardino 57 mi · Rialto 58 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
Protestant 47%unaffiliated 23%Roman Catholic 21%Jewish 2%

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 Barstow (34.8986°, -117.0228°, elevation 2,175 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. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).