Saint Charles weather in August

In August, Saint Charles sees average daytime highs of 85°F and overnight lows near 71°F, with 3.7 in of rain across 10.2 wet days and about 13.5 hours of daylight. It is the 2nd-warmest and 4th-wettest month of the year here.

Highs ease over the month, from about 86°F in the first days to 83°F by the end. The sky is clear or mostly clear about 32% of the time in August, and the air most often feels muggy.

Daylight stretches from about 14 hours at the start of August to 12 h 54 min by month's end. Set against the rest of the year, August is Saint Charles's 4th-clearest and 12th-windiest month. For the whole year in context, see Saint Charles's year-round climate.

Daytime high
85°
2nd warmest
Overnight low
71°
11th coldest
Rainfall
3.7 in
10.2 wet days
Daylight
13 h 30 min
5:26 AM – 6:57 PM
Cloud cover
56%
4th clearest
Wind
5 mph
12th windiest
Solar energy
5.38 kWh/m²
Travel score
5.4
out of 10

Saint Charles is census designated place in Charles County, Maryland, United States.

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

Temperature in August

Average highAverage lowShaded bands: 10–90% of days

Highs ease over the month, from about 86°F in the first days to 83°F by the end.

A typical August day in Saint Charles reaches about 85°F in the afternoon and slips back to 71°F overnight — a 13°F spread between the day's warmth and the night's chill. On most days the high lands between 78°F and 92°F. Set against its neighbours, August runs about 2°F cooler than July and about 6°F warmer than September.

60°70°80°90°151015202531
Avg high (°F)Avg low (°F)
18673
28673
38673
48673
58672
68572
78572
88572
98572
108572
118572
128572
138572
148572
158571
168571
178571
188471
198471
208471
218471
228471
238471
248470
258370
268370
278370
288370
298370
308369
318369

How August really feels in Saint Charles

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

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

Saint Charles weather by month

How August compares with the rest of the year at a glance. August is the 2nd-warmest and 4th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan44° / 31°3.08.72.79.60.7
Feb47° / 32°2.88.42.210.51.4
Mar55° / 39°3.910.11.511.73.5
Apr66° / 50°3.39.40136.0
May74° / 59°3.410.4014.16.7
Jun83° / 68°3.510.9014.65.7
Jul87° / 73°3.812014.44.6
Aug85° / 71°3.710.2013.55.4
Sep78° / 64°4.19.2012.36.9
Oct67° / 53°3.47.70116.6
Nov56° / 42°2.97.40.19.94.2
Dec48° / 35°3.38.71.29.41.8

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 32% of the time in August.

Beyond those clear spells, partly cloudy skies cover about 22% of August, with mostly cloudy or overcast conditions the remaining 46%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
15248
25248
35248
45446
55446
65446
75446
85446
95446
105545
115545
125545
135545
145446
155545
165545
175545
185644
195644
205644
215644
225644
235545
245545
255446
265446
275446
285446
295446
305446
315446

Chance of precipitation in August

Any precipitation

Saint Charles gets around 3.7 in of rain over 10.2 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 34% and peaks near 38% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%50%151015202531
Rain chance (%)
138
238
337
436
536
636
736
836
936
1036
1136
1237
1337
1437
1536
1636
1736
1835
1934
2034
2133
2232
2331
2431
2530
2630
2730
2830
2930
3030
3131

Humidity in August

DryComfortableHumidMuggyOppressiveMiserable

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

By dew point, August lands in the muggy band about 35% of days. Sticky, muggy-or-worse air turns up on roughly 71% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)Miserable (%)
1241634422
2251634422
3251634412
4251734412
5261733402
6261733402
7261733392
8261833392
9261833392
10261833382
11261833382
12261834382
13261934372
14271934362
15271935362
16271935352
17271936352
18271936341
19272037331
20272037331
21272038321
22282038311
23282038311
24292138301
25292137291
263102137291
273102236281
283112235271
294122334261
304122334261
314122433251

Wind in August

Winds average 5 mph in August, the calmest month.

Across August, daily wind ranges from about 5 mph on the calmest days to 5 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
15calm
25calm
35calm
45calm
55calm
65calm
75calm
85calm
95calm
105calm
115calm
125calm
135calm
145calm
155calm
165calm
175calm
185calm
195calm
205calm
215calm
225calm
235calm
245calm
255calm
265calm
275calm
285calm
295calm
305calm
315calm

Sunrise & sunset in August

DaylightNight

Daylight runs from about 14 hours at the start of August to 12 h 54 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 66 minutes over August. Sunrise moves from 5:13 AM to 5:40 AM, and sunset from 7:15 PM to 6:35 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.05:137:15
214.05:147:14
314.05:157:13
413.95:157:12
513.95:167:11
613.95:177:10
713.85:187:08
813.85:197:07
913.85:207:06
1013.75:217:05
1113.75:227:04
1213.75:237:02
1313.65:247:01
1413.65:257:00
1513.65:256:59
1613.55:266:57
1713.55:276:56
1813.45:286:55
1913.45:296:53
2013.45:306:52
2113.35:316:50
2213.35:326:49
2313.25:336:48
2413.25:346:46
2513.25:356:45
2613.15:366:43
2713.15:366:42
2813.05:376:40
2913.05:386:39
3013.05:396:37
3112.95:406:35

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 5.38 kWh/m².

For context, solar energy here swings from a low near 2 kWh/m² to a high of 6.15 kWh/m² in June across the year — August's 5.38 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
15.7Bright
25.6Bright
35.6Bright
45.6Bright
55.6Bright
65.6Bright
75.5Bright
85.5Bright
95.5Bright
105.5Bright
115.5Bright
125.5Bright
135.4Bright
145.4Bright
155.4Bright
165.4Bright
175.3Bright
185.3Bright
195.3Bright
205.3Bright
215.3Bright
225.2Bright
235.2Bright
245.2Bright
255.1Bright
265.1Bright
275.1Bright
285.0Bright
295.0Bright
305.0Bright
314.9Bright
Planning a trip in August

Hazard calendar for Saint Charles

In seasonPeak

In August, Saint Charles sits inside its atlantic hurricane season. The full year is below, with each hazard's peak months called out.

Saint Charles sits in the Atlantic hurricane belt; the season peaks August–October.

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

Is August a good time to visit Saint Charles?

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

5.4
Sightseeing
6th-best month of the year
6.9
Beach & pool
1st-best month of the year

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

What to pack for Saint Charles in August

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

In August, Saint Charles sees daytime highs around 85°F and nights near 71°F. Pack light clothes. Worth having: rain gear and sun protection. About 10 days see rain.

light clothesrain gearsun protection

Sea temperature near Saint Charles in August

The nearest coast averages about 78°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 30 mi away) is warmest in August at about 78°F and coldest in February near 37°F.

It's comfortable for a long swim from Jun 16 to Oct 6 — about 3.7 months when the water holds above 68°F.

30°40°50°60°70°80°JanFebMarAprMayJunJulAugSepOctNovDecbracingcoolrefreshingwarmtropicalcomfortable to swim
Sea temperature (°F)Comfort
Jan38Bracing
Feb37Bracing
Mar40Bracing
Apr47Bracing
May57Bracing
Jun68Refreshing
Jul76Warm
Aug78Warm
Sep74Refreshing
Oct65Cool
Nov54Bracing
Dec45Bracing

UV index in Saint Charles in August

LowModerateHighVery highExtreme

Clear-sky midday UV in August peaks around 7 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Saint Charles peaks around July 11 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 19 at about 2 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 9 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highHighModerateLowJul 11UV 9Dec 19UV 2
UV index (midday)Level
Jan2Moderate
Feb3Moderate
Mar5Moderate
Apr6High
May8Very high
Jun9Very high
Jul9Very high
Aug7High
Sep6High
Oct4Moderate
Nov3Moderate
Dec2Low

Air quality in Saint Charles 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 Saint Charles is worst in July — around 16 µg/m³ PM2.5 (moderate), about 2.2× the cleanest month (November, 7 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1416 µg/m³Nov 187 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb10Good
Mar12Good
Apr13Moderate
May14Moderate
Jun15Moderate
Jul16Moderate
Aug14Moderate
Sep11Good
Oct8Good
Nov7Good
Dec8Good
Location & terrain

Where is Saint Charles?

Saint Charles sits at 38.6°N, 76.9°W, 200 ft above sea level, in United States. The nearest listed city is St. Charles, 0.6 mi away.

Topography around Saint Charles

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

Within 2 miles, the terrain around Saint Charles has only modest variations in elevation — a maximum elevation change of 98 ft around an average of 213 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 312 ft; within 50 miles, significant variations in elevation — a maximum elevation change of 1,539 ft.

The land around Saint Charles is covered by trees (61%) and artificial surfaces (24%) within 2 miles, trees (77%) within 10 miles, and trees (60%) and water (20%) within 50 miles.

2 miles
98 ft
10 miles
312 ft
50 miles
1,539 ft
treesgrasslandcroplandartificial surfaceswaterwetland
August weather nearby: St. Charles 0.6 mi · Waldorf 1.2 mi · Fort Washington 8.7 mi · Fort Hunt 11 mi · Clinton 11 mi · Hybla Valley 12 mi · Woodlawn 13 mi · Oxon Hill-Glassmanor 14 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 Saint Charles (38.6032°, -76.9386°, elevation 200 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. Tropical-cyclone seasons are the published climatological basin seasons (NOAA National Hurricane Center / regional warning centres). 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).