Montclair weather in August

In August, Montclair sees average daytime highs of 87°F and overnight lows near 65°F, with 0.0 in of rain across 0.2 wet days and about 13.3 hours of daylight. It is the 1st-warmest and 12th-wettest month of the year here.

Day-to-day highs hold fairly steady near 87°F through the month. The sky is clear or mostly clear about 91% of the time in August, and the air most often feels comfortable.

Daylight stretches from about 13 h 42 min at the start of August to 12 h 48 min by month's end. Set against the rest of the year, August is Montclair's 1st-clearest and 10th-windiest month. For the whole year in context, see Montclair's year-round climate.

Daytime high
87°
1st warmest
Overnight low
65°
12th coldest
Rainfall
0.0 in
0.2 wet days
Daylight
13 h 18 min
5:16 AM – 6:33 PM
Cloud cover
11%
1st clearest
Wind
3 mph
10th windiest
Solar energy
7.4 kWh/m²
Travel score
6.5
out of 10

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

Density
2,708/km²
people per km²
Founded
1956

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

Temperature in August

Average highAverage lowShaded bands: 10–90% of days

Day-to-day highs hold fairly steady near 87°F through the month.

A typical August day in Montclair reaches about 87°F in the afternoon and slips back to 65°F overnight — a 22°F spread between the day's warmth and the night's chill. On most days the high lands between 80°F and 94°F. Set against its neighbours, August runs about 2°F warmer than July and about 3°F warmer than September.

60°70°80°90°151015202531
Avg high (°F)Avg low (°F)
18665
28665
38665
48665
58665
68665
78765
88765
98765
108765
118765
128765
138765
148765
158765
168765
178765
188765
198765
208765
218765
228765
238765
248765
258765
268765
278765
288765
298765
308765
318765

Montclair weather by month

How August compares with the rest of the year at a glance. August is the 1st-warmest and 12th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysDaylight (hours)Travel score
Jan63° / 44°3.65.9106.2
Feb63° / 46°4.06.610.76.2
Mar66° / 48°2.46.311.76.8
Apr70° / 51°1.03.712.87.8
May74° / 55°0.42.213.78.6
Jun79° / 59°0.10.314.28.9
Jul85° / 64°0.10.5147.1
Aug87° / 65°0.00.213.36.5
Sep84° / 63°0.20.912.27.4
Oct78° / 57°0.72.611.18.7
Nov69° / 49°1.02.810.28.0
Dec62° / 44°2.55.39.86.3

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 91% of the time in August, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 4% of August, with mostly cloudy or overcast conditions the remaining 4%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
1937
2937
3937
4937
5946
6946
7955
8955
9964
10964
11964
12964
13964
14964
15973
16973
17973
18973
19964
20964
21964
22964
23964
24964
25964
26964
27964
28964
29964
30964
31964

Chance of precipitation in August

Any precipitation

Montclair gets around 0.0 in of rain over 0.2 wet days in August, the driest month. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 1% and peaks near 2% on the wettest days.

0%10%20%30%151015202531
Rain chance (%)
11
21
31
41
51
61
71
81
91
101
111
120
130
140
150
160
170
180
190
200
210
220
231
241
251
261
271
282
292
302
312

Humidity in August

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, August lands in the comfortable band about 46% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)
11546345
21646345
31646345
41745334
51845334
61845324
71945324
82045314
92045314
102045314
112145304
122146304
132146303
142047293
152047293
162048293
172048293
182049293
192049293
202049293
212049292
222048292
232148292
242147292
252247293
262246293
272345303
282344303
292443303
302442303
312542304

Wind in August

Winds average 3 mph in August.

Across August, 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.

0246810151015202531
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
313calm

Sunrise & sunset in August

DaylightNight

Daylight runs from about 13 h 42 min at the start of August to 12 h 48 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 54 minutes over August. Sunrise moves from 5:05 AM to 5:27 AM, and sunset from 6:48 PM to 6:14 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.75:056:48
213.75:066:47
313.75:076:47
413.65:086:46
513.65:086:45
613.65:096:44
713.65:106:43
813.55:106:42
913.55:116:41
1013.55:126:40
1113.45:136:39
1213.45:136:38
1313.45:146:37
1413.35:156:36
1513.35:166:34
1613.35:166:33
1713.25:176:32
1813.25:186:31
1913.25:196:30
2013.25:196:29
2113.15:206:27
2213.15:216:26
2313.15:226:25
2413.05:226:24
2513.05:236:22
2613.05:246:21
2712.95:246:20
2812.95:256:18
2912.85:266:17
3012.85:276:16
3112.85:276:14

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 7.4 kWh/m².

For context, solar energy here swings from a low near 2.95 kWh/m² to a high of 8.05 kWh/m² in June across the year — August's 7.4 kWh/m² sits near the top of that range.

02468151015202531
Solar energy (kWh/m²)Level
17.7Intense
27.7Intense
37.7Intense
47.6Intense
57.6Intense
67.6Intense
77.6Intense
87.6Intense
97.6Intense
107.5Intense
117.5Intense
127.5Intense
137.5Intense
147.5Intense
157.4Intense
167.4Intense
177.4Intense
187.3Intense
197.3Intense
207.3Intense
217.3Intense
227.2Intense
237.2Intense
247.2Intense
257.1Intense
267.1Intense
277.0Intense
287.0Intense
297.0Intense
306.9Intense
316.9Intense
Planning a trip in August

Is August a good time to visit Montclair?

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

6.5
Sightseeing
9th-best month of the year
9.1
Beach & pool
2nd-best month of the year

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

What to pack for Montclair in August

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

In August, Montclair sees daytime highs around 87°F and nights near 65°F. Pack light clothes and sun protection.

light clothessun protection

Sea temperature near Montclair in August

The nearest coast averages about 69°F in August — the other half of the beach question. The full-year curve and swim-comfort zones are below.

The sea at the nearest coast (about 33 mi away) is warmest in August at about 69°F and coldest in February near 59°F.

It's comfortable for a long swim from Jul 13 to Sep 28 — about 2.6 months when the water holds above 68°F.

60°65°70°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingcomfortable to swim
Sea temperature (°F)Comfort
Jan59Cool
Feb59Cool
Mar59Cool
Apr60Cool
May63Cool
Jun65Cool
Jul68Refreshing
Aug69Refreshing
Sep69Refreshing
Oct67Cool
Nov64Cool
Dec60Cool

UV index in Montclair in August

LowModerateHighVery highExtreme

Clear-sky midday UV in August peaks around 10 (very high — sun protection essential). The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Montclair peaks around July 12 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 highHighModerateJul 12UV 11Dec 16UV 3
UV index (midday)Level
Jan4Moderate
Feb5Moderate
Mar5Moderate
Apr8Very high
May8Very high
Jun11Extreme
Jul11Extreme
Aug10Extreme
Sep8Very high
Oct6High
Nov3Moderate
Dec3Moderate

Air quality in Montclair in August

GoodModeratePoorUnhealthyVery unhealthy

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

Air quality in Montclair is worst in September — around 49 µg/m³ PM2.5 (poor), about 4.0× the cleanest month (May, 12 µg/m³).

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

0204060JanFebMarAprMayJunJulAugSepOctNovDecModeratePoorModerateSep 1447 µg/m³May 1713 µg/m³
PM2.5 (µg/m³)Level
Jan18Moderate
Feb19Moderate
Mar19Moderate
Apr17Moderate
May12Moderate
Jun17Moderate
Jul19Moderate
Aug32Moderate
Sep49Poor
Oct21Moderate
Nov21Moderate
Dec18Moderate
Location & terrain

Where is Montclair?

Montclair sits at 34.1°N, 117.7°W, 1,066 ft above sea level, in United States. The nearest listed city is Claremont, 1.9 mi away.

Topography around Montclair

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

Within 2 miles, the terrain around Montclair has only modest variations in elevation — a maximum elevation change of 459 ft around an average of 1,076 ft above sea level; within 10 miles, very significant variations in elevation — a maximum elevation change of 7,526 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 11,430 ft.

The land around Montclair is covered by artificial surfaces (86%) within 2 miles, artificial surfaces (53%) within 10 miles, and artificial surfaces (26%), shrubs (21%) and grassland (20%) within 50 miles.

2 miles
459 ft
10 miles
7,526 ft
50 miles
11,430 ft
treesshrubsgrasslandcroplandartificial surfacesbare terrainwater
August weather nearby: Claremont 1.9 mi · Ontario 2.5 mi · Upland 2.5 mi · Pomona 3.7 mi · Chino 4.3 mi · La Verne 5.0 mi · Rancho Cucamonga 5.6 mi · San Dimas 6.8 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 Montclair (34.0775°, -117.6898°, elevation 1,066 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. Sea temperatures are the NOAA OISST v2.1 1991–2020 monthly climatology (public domain), sampled at the nearest ocean point. 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).