Monrovia weather in August

In August, Monrovia sees average daytime highs of 88°F and overnight lows near 65°F, with 0.2 in of rain across 1.9 wet days and about 13.3 hours of daylight. It is the 1st-warmest and 11th-wettest month of the year here.

Day-to-day highs hold fairly steady near 88°F through the month. The sky is clear or mostly clear about 89% of the time in August, and the air most often feels dry.

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 Monrovia's 1st-clearest and 11th-windiest month. For the whole year in context, see Monrovia's year-round climate.

Daytime high
88°
1st warmest
Overnight low
65°
12th coldest
Rainfall
0.2 in
1.9 wet days
Daylight
13 h 18 min
5:18 AM – 6:35 PM
Cloud cover
13%
1st clearest
Wind
3 mph
11th windiest
Solar energy
7.45 kWh/m²
Travel score
6.0
out of 10

Monrovia is city in the San Gabriel Valley of Los Angeles County, California, United States.

Density
1,055/km²
people per km²
Founded
1887

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 88°F through the month.

A typical August day in Monrovia reaches about 88°F in the afternoon and slips back to 65°F overnight — a 23°F spread between the day's warmth and the night's chill. On most days the high lands between 81°F and 95°F. Set against its neighbours, August runs on par with July and about 4°F warmer than September.

50°60°70°80°90°151015202531
Avg high (°F)Avg low (°F)
18765
28765
38765
48765
58765
68865
78865
88865
98865
108865
118865
128865
138865
148865
158865
168865
178865
188865
198865
208865
218865
228865
238865
248865
258865
268865
278865
288765
298765
308765
318765

Monrovia weather by month

How August compares with the rest of the year at a glance. August is the 1st-warmest and 11th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan59° / 42°3.55.91.1105.3
Feb60° / 43°3.86.91.510.75.2
Mar63° / 45°2.56.7111.76.3
Apr68° / 47°1.040.312.87.6
May73° / 53°0.53013.88.5
Jun81° / 58°0.10.7014.28.5
Jul86° / 64°0.42.10146.4
Aug88° / 65°0.21.9013.36.0
Sep84° / 61°0.31.8012.27.5
Oct76° / 55°0.82.6011.18.7
Nov66° / 47°0.92.90.210.27.6
Dec59° / 42°2.45.20.79.85.3

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 89% of the time in August, the clearest month of the year.

Beyond those clear spells, partly cloudy skies cover about 6% of August, with mostly cloudy or overcast conditions the remaining 4%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
1937
2937
3946
4946
5946
6946
7955
8955
9964
10964
11973
12973
13973
14973
15973
16973
17973
18973
19973
20973
21973
22964
23964
24964
25955
26955
27955
28955
29955
30955
31955

Chance of precipitation in August

Any precipitation

Monrovia gets around 0.2 in of rain over 1.9 wet days in August. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable rain averages around 7% and peaks near 8% on the wettest days.

0%10%20%30%151015202531
Rain chance (%)
16
26
36
46
56
66
76
86
96
106
116
126
136
147
157
167
177
187
197
207
216
226
236
247
257
267
277
288
298
308
318

Humidity in August

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, August lands in the dry band about 74% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)
166286
267276
369265
470255
571245
671245
772235
873234
974224
1074224
1174224
1274224
1374224
1474224
1574224
1674224
1774224
1874224
1975223
2075223
2175223
2276213
2376213
2476213
2577203
2677203
2778193
2877194
2977194
3077194
3178184

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 5:06 AM to 5:29 AM, and sunset from 6:50 PM to 6:16 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
113.75:066:50
213.75:076:49
313.75:086:48
413.65:096:47
513.65:096:46
613.65:106:45
713.65:116:44
813.55:126:43
913.55:126:42
1013.55:136:41
1113.45:146:40
1213.45:156:39
1313.45:156:38
1413.35:166:37
1513.35:176:36
1613.35:186:35
1713.35:186:33
1813.25:196:32
1913.25:206:31
2013.25:216:30
2113.15:216:29
2213.15:226:27
2313.15:236:26
2413.05:236:25
2513.05:246:24
2613.05:256:22
2712.95:266:21
2812.95:266:20
2912.95:276:18
3012.85:286:17
3112.85:296:16

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 7.45 kWh/m².

For context, solar energy here swings from a low near 2.96 kWh/m² to a high of 8.18 kWh/m² in June across the year — August's 7.45 kWh/m² falls in the middle.

02468151015202531
Solar energy (kWh/m²)Level
17.7Intense
27.7Intense
37.7Intense
47.7Intense
57.7Intense
67.7Intense
77.7Intense
87.7Intense
97.6Intense
107.6Intense
117.6Intense
127.6Intense
137.5Intense
147.5Intense
157.5Intense
167.5Intense
177.4Intense
187.4Intense
197.4Intense
207.3Intense
217.3Intense
227.3Intense
237.2Intense
247.2Intense
257.2Intense
267.1Intense
277.1Intense
287.0Intense
297.0Intense
307.0Intense
316.9Intense
Planning a trip in August

Is August a good time to visit Monrovia?

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

6.0
Sightseeing
9th-best month of the year
8.7
Beach & pool
4th-best month of the year

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

What to pack for Monrovia in August

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

In August, Monrovia sees daytime highs around 88°F and nights near 65°F. Pack light clothes and sun protection.

light clothessun protection

Sea temperature near Monrovia in August

The nearest coast averages about 68°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 29 mi away) is warmest in August at about 68°F and coldest in February near 59°F.

It's comfortable for a long swim from Aug 4 to Sep 13 — about 1.3 months when the water holds above 68°F.

60°65°70°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshing
Sea temperature (°F)Comfort
Jan59Bracing
Feb59Bracing
Mar59Bracing
Apr59Cool
May62Cool
Jun65Cool
Jul67Cool
Aug68Refreshing
Sep68Refreshing
Oct66Cool
Nov63Cool
Dec60Cool

UV index in Monrovia 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 Monrovia peaks around July 11 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.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateVery highExtremeVery highHighModerateJul 11UV 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 Monrovia 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 Monrovia is worst in September — around 39 µg/m³ PM2.5 (poor), about 3.2× the cleanest month (May, 12 µg/m³).

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

010203040JanFebMarAprMayJunJulAugSepOctNovDecModerateModerateSep 1537 µg/m³May 1612 µg/m³
PM2.5 (µg/m³)Level
Jan14Moderate
Feb15Moderate
Mar16Moderate
Apr14Moderate
May12Moderate
Jun15Moderate
Jul18Moderate
Aug22Moderate
Sep39Poor
Oct15Moderate
Nov17Moderate
Dec14Moderate
Location & terrain

Where is Monrovia?

Monrovia sits at 34.1°N, 118.0°W, 571 ft above sea level, in United States. The nearest listed city is Duarte, 1.2 mi away.

Topography around Monrovia

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

Within 2 miles, the terrain around Monrovia has significant variations in elevation — a maximum elevation change of 1,785 ft around an average of 686 ft above sea level; within 10 miles, very significant variations in elevation — a maximum elevation change of 5,932 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 10,013 ft.

The land around Monrovia is covered by artificial surfaces (58%) and trees (31%) within 2 miles, artificial surfaces (43%), shrubs (27%) and trees (23%) within 10 miles, and artificial surfaces (26%) and grassland (20%) within 50 miles.

2 miles
1,785 ft
10 miles
5,932 ft
50 miles
10,013 ft
treesshrubsgrasslandcroplandartificial surfacesbare terrainwater
August weather nearby: Duarte 1.2 mi · Arcadia 1.9 mi · Temple City 4.3 mi · Baldwin Park 5.0 mi · Azusa 5.6 mi · El Monte 5.6 mi · Rosemead 6.2 mi · West Covina 6.2 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 Monrovia (34.1481°, -117.9989°, elevation 571 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).