Yucaipa weather in September

In September, Yucaipa sees average daytime highs of 83°F and overnight lows near 61°F, with 0.3 in of rain across 1.7 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 86°F in the first days to 80°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 Yucaipa's 1st-clearest and 10th-windiest month. For the whole year in context, see Yucaipa's year-round climate.

Daytime high
83°
3rd warmest
Overnight low
61°
10th coldest
Rainfall
0.3 in
1.7 wet days
Daylight
12 h 12 min
5:36 AM – 5:49 PM
Cloud cover
14%
1st clearest
Wind
3 mph
10th windiest
Solar energy
6.29 kWh/m²
Travel score
7.7
out of 10

Yucaipa is city in San Bernardino County, California.

Density
725/km²
people per km²
Founded
1989

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 86°F in the first days to 80°F by the end.

A typical September day in Yucaipa reaches about 83°F in the afternoon and slips back to 61°F overnight — a 22°F spread between the day's warmth and the night's chill. On most days the high lands between 74°F and 91°F. Set against its neighbours, September runs about 4°F cooler than August and about 9°F warmer than October.

40°60°80°151015202530
Avg high (°F)Avg low (°F)
18664
28664
38664
48664
58664
68563
78563
88563
98562
108462
118462
128462
138461
148361
158361
168360
178360
188360
198260
208259
218259
228259
238259
248258
258158
268158
278158
288057
298057
308057

Yucaipa 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.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan57° / 39°2.66.11.1104.7
Feb58° / 40°3.17.31.410.74.7
Mar62° / 42°1.96.3111.75.9
Apr66° / 45°1.04.10.412.87.4
May73° / 51°0.52.9013.78.5
Jun81° / 58°0.10.9014.28.4
Jul87° / 64°0.52.80146.2
Aug87° / 65°0.43013.36.0
Sep83° / 61°0.31.7012.27.7
Oct74° / 52°0.62.4011.18.7
Nov64° / 44°0.93.30.210.27.2
Dec57° / 39°2.15.10.79.84.7

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 5% of September, with mostly cloudy or overcast conditions the remaining 7%.

0%25%50%75%100%151015202530
Clearer (%)Cloudier (%)
1946
2946
3946
4946
5946
6946
7946
8955
9955
10955
11955
12955
13955
14955
15955
16955
17946
18937
19937
20937
21937
22937
23937
24919
25919
26919
27919
28919
29919
30919

Chance of precipitation in September

Any precipitation

Yucaipa gets around 0.3 in of rain over 1.7 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 6% and peaks near 10% on the wettest days.

0%10%20%30%151015202530
Rain chance (%)
110
210
39
49
59
68
78
87
97
106
116
125
135
144
154
164
174
184
194
204
214
224
234
244
254
264
274
284
294
304

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 89% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202530
Dry (%)Comfortable (%)Humid (%)
178166
278166
379156
480155
580155
681145
782144
883134
984133
1085123
1186122
1287112
1388102
148992
159181
169181
179271
189271
199361
209361
219361
229451
239451
249451
259451
269451
279541
289541
299541
309730

Wind in September

Winds average 3 mph in September.

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

0246810151015202530
Wind speed (mph)Feels
13calm
23calm
33calm
43calm
53calm
63calm
73calm
83calm
93calm
103calm
113calm
123calm
133calm
143calm
153calm
163calm
173calm
183calm
193calm
203calm
213calm
223calm
233calm
243calm
253calm
263calm
273calm
283calm
293calm
303calm

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 5:46 AM, and sunset from 6:10 PM to 5:29 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202530
Daylight (h)Sunrise (AM)Sunset (PM)
112.75:266:10
212.75:266:09
312.75:276:07
412.65:286:06
512.65:286:05
612.65:296:03
712.55:306:02
812.55:316:00
912.55:315:59
1012.45:325:57
1112.45:335:56
1212.45:335:55
1312.35:345:53
1412.35:355:52
1512.25:365:50
1612.25:365:49
1712.25:375:47
1812.15:385:46
1912.15:385:44
2012.15:395:43
2112.05:405:41
2212.05:415:40
2312.05:415:39
2411.95:425:37
2511.95:435:36
2611.85:435:34
2711.85:445:33
2811.85:455:31
2911.75:465:30
3011.75:465:29

Solar energy in September

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in September, about 6.29 kWh/m².

For context, solar energy here swings from a low near 3.07 kWh/m² to a high of 8.41 kWh/m² in June across the year — September's 6.29 kWh/m² falls in the middle.

0246151015202530
Solar energy (kWh/m²)Level
16.7Intense
26.7Intense
36.6Intense
46.6Intense
56.6Intense
66.6Intense
76.5Intense
86.5Intense
96.5Intense
106.5Intense
116.5Intense
126.4Intense
136.4Intense
146.4Intense
156.4Intense
166.3Intense
176.3Intense
186.3Intense
196.2Intense
206.2Intense
216.1Intense
226.1Intense
236.1Intense
246.0Intense
256.0Bright
265.9Bright
275.9Bright
285.8Bright
295.8Bright
305.8Bright
Planning a trip in September

Is September a good time to visit Yucaipa?

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

7.7
Sightseeing
4th-best month of the year
8.9
Beach & pool
1st-best month of the year

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

What to pack for Yucaipa in September

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

In September, Yucaipa sees daytime highs around 83°F and nights near 61°F. Pack light clothes and sun protection.

light clothessun protection

UV index in Yucaipa 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 Yucaipa 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.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highHighModerateJun 23UV 11Dec 16UV 3
UV index (midday)Level
Jan4Moderate
Feb5Moderate
Mar5High
Apr8Very high
May8Very high
Jun11Extreme
Jul11Extreme
Aug11Extreme
Sep8Very high
Oct6High
Nov4Moderate
Dec3Moderate

Air quality in Yucaipa 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 Yucaipa is worst in September — around 40 µg/m³ PM2.5 (poor), about 5.4× the cleanest month (December, 7 µg/m³).

Modeled monthly averages (CAMS reanalysis, 2015–2024).

010203040JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateModerateGoodSep 1437 µg/m³Dec 207 µg/m³
PM2.5 (µg/m³)Level
Jan8Good
Feb9Good
Mar11Good
Apr10Good
May8Good
Jun19Moderate
Jul12Moderate
Aug20Moderate
Sep40Poor
Oct10Good
Nov8Good
Dec7Good
Location & terrain

Where is Yucaipa?

Yucaipa sits at 34.0°N, 117.0°W, 2,618 ft above sea level, in United States. The nearest listed city is Beaumont, 8.1 mi away.

Topography around Yucaipa

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

Within 2 miles, the terrain around Yucaipa has significant variations in elevation — a maximum elevation change of 1,558 ft around an average of 2,700 ft above sea level; within 10 miles, extreme variations in elevation — a maximum elevation change of 9,577 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 11,404 ft.

The land around Yucaipa is covered by artificial surfaces (49%) within 2 miles, shrubs (39%) and grassland (26%) within 10 miles, and shrubs (30%) and bare terrain (21%) within 50 miles.

2 miles
1,558 ft
10 miles
9,577 ft
50 miles
11,404 ft
treesshrubsgrasslandcroplandartificial surfacesbare terrainwater
September weather nearby: Beaumont 8.1 mi · Redlands 8.1 mi · Highland 12 mi · Banning 12 mi · Loma Linda 12 mi · Moreno Valley 12 mi · San Bernardino 15 mi · Colton 16 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 Yucaipa (34.0336°, -117.0431°, elevation 2,618 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).