Castle Rock weather in August

In August, Castle Rock sees average daytime highs of 79°F and overnight lows near 52°F, with 2.0 in of rain across 10.1 wet days and about 13.5 hours of daylight. It is the 2nd-warmest and 5th-wettest month of the year here.

Day-to-day highs hold fairly steady near 79°F through the month. The sky is clear or mostly clear about 39% of the time in August, and the air most often feels dry.

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 Castle Rock's 8th-clearest and 12th-windiest month. For the whole year in context, see Castle Rock's year-round climate.

Daytime high
79°
2nd warmest
Overnight low
52°
11th coldest
Rainfall
2.0 in
10.1 wet days
Daylight
13 h 36 min
5:17 AM – 6:50 PM
Cloud cover
49%
8th clearest
Wind
5 mph
12th windiest
Solar energy
6.46 kWh/m²
Travel score
6.9
out of 10

Castle Rock is town in and seat of Douglas County, Colorado, United States.

Density
635/km²
people per km²
Founded
1874

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 79°F through the month.

A typical August day in Castle Rock reaches about 79°F in the afternoon and slips back to 52°F overnight — a 27°F spread between the day's warmth and the night's chill. On most days the high lands between 71°F and 86°F. Set against its neighbours, August runs about 2°F cooler than July and about 7°F warmer than September.

40°60°80°151015202531
Avg high (°F)Avg low (°F)
18054
28054
38054
48053
58053
68053
78053
87953
97953
107953
117953
127953
137953
147953
157952
167952
177952
187952
197952
207952
217952
227952
237952
247851
257851
267851
277851
287851
297851
307750
317750

How August really feels in Castle Rock

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.

Castle Rock weather by month

How August compares with the rest of the year at a glance. August is the 2nd-warmest and 5th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan39° / 12°0.64.24.79.50.0
Feb42° / 15°0.755.410.50.3
Mar49° / 22°1.76.95.911.72.2
Apr55° / 28°2.69.76.1133.5
May65° / 39°3.012.31.714.15.5
Jun76° / 48°2.110.20.114.76.8
Jul81° / 54°2.510.9014.56.5
Aug79° / 52°2.010.1013.56.9
Sep72° / 45°1.36.40.512.37.6
Oct60° / 32°1.45.52.4115.7
Nov48° / 21°1.04.94.99.82.0
Dec39° / 12°0.73.94.49.30.0

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 39% of the time in August.

Beyond those clear spells, partly cloudy skies cover about 29% of August, with mostly cloudy or overcast conditions the remaining 31%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
16238
26337
36337
46436
56436
66535
76535
86634
96634
106733
116733
126832
136931
146931
157030
167030
177030
187030
197030
207030
217030
227030
237030
247030
257129
267129
277228
287327
297327
307426
317327

Chance of precipitation in August

Any precipitation

Castle Rock gets around 2.0 in of rain over 10.1 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 32% and peaks near 39% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%50%151015202531
Rain chance (%)
139
239
339
438
538
637
737
837
936
1036
1135
1234
1333
1433
1532
1631
1731
1830
1930
2030
2129
2229
2328
2428
2528
2627
2727
2826
2926
3026
3125

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 96% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)
18812
28812
38911
49010
5919
6919
7928
8937
9946
10946
11955
12964
13964
14973
15973
16973
17973
18982
19982
20982
21982
22982
23982
24982
25991
26991
27991
28991
29991
30991
31991

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 5:03 AM to 5:31 AM, and sunset from 7:08 PM to 6:28 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.15:037:08
214.15:047:07
314.05:057:06
414.05:067:05
514.05:067:04
613.95:077:03
713.95:087:02
813.95:097:00
913.85:106:59
1013.85:116:58
1113.75:126:57
1213.75:136:56
1313.75:146:54
1413.65:156:53
1513.65:166:52
1613.65:176:50
1713.55:186:49
1813.55:196:47
1913.45:206:46
2013.45:216:45
2113.45:226:43
2213.35:236:42
2313.35:236:40
2413.25:246:39
2513.25:256:37
2613.25:266:36
2713.15:276:34
2813.15:286:33
2913.05:296:31
3013.05:306:29
3112.95:316:28

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 6.46 kWh/m².

For context, solar energy here swings from a low near 2.61 kWh/m² to a high of 7.41 kWh/m² in June across the year — August's 6.46 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
16.7Intense
26.7Intense
36.7Intense
46.7Intense
56.7Intense
66.7Intense
76.7Intense
86.6Intense
96.6Intense
106.6Intense
116.6Intense
126.6Intense
136.6Intense
146.5Intense
156.5Intense
166.5Intense
176.5Intense
186.5Intense
196.4Intense
206.4Intense
216.4Intense
226.3Intense
236.3Intense
246.3Intense
256.3Intense
266.2Intense
276.2Intense
286.2Intense
296.1Intense
306.1Intense
316.1Intense
Planning a trip in August

Is August a good time to visit Castle Rock?

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

6.9
Sightseeing
2nd-best month of the year
6.6
Beach & pool
2nd-best month of the year

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

What to pack for Castle Rock in August

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

In August, Castle Rock sees daytime highs around 79°F and nights near 52°F. Pack sun protection. Worth having: light clothes and rain gear. About 10 days see rain.

sun protectionlight clothesrain gear

UV index in Castle Rock 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 Castle Rock peaks around July 15 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 22 at about 2 (moderate).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 10 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highHighModerateJul 15UV 11Dec 22UV 2
UV index (midday)Level
Jan3Moderate
Feb4Moderate
Mar7Very high
Apr7High
May8Very high
Jun11Extreme
Jul11Extreme
Aug10Extreme
Sep8Very high
Oct6High
Nov4Moderate
Dec2Moderate
Location & terrain

Where is Castle Rock?

Castle Rock sits at 39.4°N, 104.9°W, 6,224 ft above sea level, in United States. The nearest listed city is Parker, 11 mi away.

Topography around Castle Rock

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

Within 2 miles, the terrain around Castle Rock has only modest variations in elevation — a maximum elevation change of 646 ft around an average of 6,368 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 2,028 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 9,268 ft.

The land around Castle Rock is covered by grassland (52%) and artificial surfaces (28%) within 2 miles, grassland (74%) within 10 miles, and grassland (55%) and trees (29%) within 50 miles.

2 miles
646 ft
10 miles
2,028 ft
50 miles
9,268 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
August weather nearby: Parker 11 mi · Highlands Ranch 14 mi · Centennial 14 mi · Castlewood 15 mi · Southglenn 16 mi · Greenwood Village 17 mi · Littleton 19 mi · Columbine 19 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 Castle Rock (39.3722°, -104.8561°, elevation 6,224 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. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).