Reston weather in August

In August, Reston sees average daytime highs of 85°F and overnight lows near 68°F, with 3.6 in of rain across 10.8 wet days and about 13.5 hours of daylight. It is the 2nd-warmest and 6th-wettest month of the year here.

Highs ease over the month, from about 87°F in the first days to 84°F by the end. The sky is clear or mostly clear about 28% of the time in August, and the air most often feels muggy.

Daylight stretches from about 14 h 06 min at the start of August to 12 h 54 min by month's end. Set against the rest of the year, August is Reston's 4th-clearest and 12th-windiest month. For the whole year in context, see Reston's year-round climate.

Daytime high
85°
2nd warmest
Overnight low
68°
11th coldest
Rainfall
3.6 in
10.8 wet days
Daylight
13 h 30 min
5:27 AM – 7:00 PM
Cloud cover
58%
4th clearest
Wind
5 mph
12th windiest
Solar energy
5.33 kWh/m²
Travel score
5.0
out of 10

Reston is census-designated place in Fairfax County, Virginia, United States.

Density
1,441/km²
people per km²
Founded
1964

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 87°F in the first days to 84°F by the end.

A typical August day in Reston reaches about 85°F in the afternoon and slips back to 68°F overnight — a 17°F spread between the day's warmth and the night's chill. On most days the high lands between 78°F and 93°F. Set against its neighbours, August runs about 2°F cooler than July and about 7°F warmer than September.

60°70°80°90°151015202531
Avg high (°F)Avg low (°F)
18770
28770
38770
48770
58770
68769
78669
88669
98669
108669
118669
128669
138669
148669
158669
168568
178568
188568
198568
208568
218568
228568
238567
248567
258567
268467
278467
288467
298467
308466
318366

How August really feels in Reston

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.

Reston weather by month

How August compares with the rest of the year at a glance. August is the 2nd-warmest and 6th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan42° / 28°3.18.439.60.3
Feb46° / 29°2.88.32.810.51.1
Mar54° / 36°3.910.21.911.73.3
Apr65° / 47°3.410.10.1135.8
May74° / 56°3.911.4014.16.5
Jun83° / 65°3.611.2014.75.5
Jul88° / 70°4.111.7014.54.3
Aug85° / 68°3.610.8013.55.0
Sep78° / 61°4.59.3012.36.8
Oct67° / 49°3.57.80116.5
Nov56° / 39°3.07.50.29.93.9
Dec46° / 32°3.591.89.31.4

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 28% of the time in August.

Beyond those clear spells, partly cloudy skies cover about 24% of August, with mostly cloudy or overcast conditions the remaining 48%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
14852
24852
34951
44951
54951
65050
75050
85050
95050
105050
115149
125149
135248
145248
155248
165347
175347
185446
195446
205446
215446
225446
235347
245347
255347
265347
275248
285248
295248
305248
315149

Chance of precipitation in August

Any precipitation

Reston gets around 3.6 in of rain over 10.8 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 35% 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
437
537
637
737
837
937
1037
1137
1237
1337
1437
1537
1636
1736
1835
1935
2034
2134
2233
2333
2432
2532
2631
2731
2831
2931
3031
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 32% of days. Sticky, muggy-or-worse air turns up on roughly 50% of them.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)Muggy (%)Oppressive (%)
1813233621
2813233521
3913233521
4913223421
5913223421
61013223421
71013223321
81013223321
91013223321
101113223321
111113233321
121113233320
131113233320
141112243320
151112243319
161112253319
171112253318
181113263317
191113273317
201113273316
211113273315
221114283315
231114283214
241115283214
251216273114
261217273014
271317272914
281418262814
291518262814
301519252713
311619252613

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 h 06 min 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 72 minutes over August. Sunrise moves from 5:14 AM to 5:41 AM, and sunset from 7:17 PM to 6:37 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.15:147:17
214.05:157:16
314.05:157:15
414.05:167:14
513.95:177:13
613.95:187:12
713.95:197:11
813.85:207:10
913.85:217:08
1013.85:227:07
1113.75:237:06
1213.75:247:05
1313.65:257:03
1413.65:267:02
1513.65:267:01
1613.55:277:00
1713.55:286:58
1813.55:296:57
1913.45:306:55
2013.45:316:54
2113.35:326:53
2213.35:336:51
2313.35:346:50
2413.25:356:48
2513.25:366:47
2613.15:376:45
2713.15:386:44
2813.15:396:42
2913.05:406:41
3013.05:406:39
3112.95:416:37

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 5.33 kWh/m².

For context, solar energy here swings from a low near 1.95 kWh/m² to a high of 6.14 kWh/m² in June across the year — August's 5.33 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
15.6Bright
25.6Bright
35.6Bright
45.6Bright
55.6Bright
65.5Bright
75.5Bright
85.5Bright
95.5Bright
105.5Bright
115.4Bright
125.4Bright
135.4Bright
145.4Bright
155.3Bright
165.3Bright
175.3Bright
185.3Bright
195.3Bright
205.2Bright
215.2Bright
225.2Bright
235.1Bright
245.1Bright
255.1Bright
265.0Bright
275.0Bright
285.0Bright
294.9Bright
304.9Bright
314.9Bright
Planning a trip in August

Is August a good time to visit Reston?

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

5.0
Sightseeing
6th-best month of the year
6.7
Beach & pool
1st-best month of the year

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

What to pack for Reston in August

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

In August, Reston sees daytime highs around 85°F and nights near 68°F. Pack light clothes. Worth having: rain gear and sun protection. About 11 days see rain.

light clothesrain gearsun protection

UV index in Reston 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 Reston 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
Mar5High
Apr6High
May8Very high
Jun9Very high
Jul9Very high
Aug7High
Sep6High
Oct4Moderate
Nov3Moderate
Dec2Low

Air quality in Reston 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 Reston is worst in July — around 17 µg/m³ PM2.5 (moderate), about 1.9× the cleanest month (November, 9 µg/m³).

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

01020JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodJul 1317 µg/m³Nov 129 µg/m³
PM2.5 (µg/m³)Level
Jan11Good
Feb12Moderate
Mar13Moderate
Apr13Moderate
May15Moderate
Jun16Moderate
Jul17Moderate
Aug15Moderate
Sep12Moderate
Oct9Good
Nov9Good
Dec10Good
Location & terrain

Where is Reston?

Reston sits at 39.0°N, 77.3°W, 328 ft above sea level, in United States. The nearest listed city is Herndon, 2.5 mi away.

Topography around Reston

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

Within 2 miles, the terrain around Reston has only modest variations in elevation — a maximum elevation change of 302 ft around an average of 377 ft above sea level; within 10 miles, only modest variations in elevation — a maximum elevation change of 623 ft; within 50 miles, large variations in elevation — a maximum elevation change of 3,514 ft.

The land around Reston is covered by trees (69%) and artificial surfaces (21%) within 2 miles, trees (70%) within 10 miles, and trees (64%) within 50 miles.

2 miles
302 ft
10 miles
623 ft
50 miles
3,514 ft
treesgrasslandcroplandartificial surfaceswater
August weather nearby: Herndon 2.5 mi · Great Falls 3.7 mi · Wolf Trap 3.7 mi · Oak Hill 4.3 mi · Sterling 5.6 mi · Vienna 6.2 mi · Oakton 6.2 mi · Tysons 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 Reston (38.9687°, -77.3411°, elevation 328 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).