Thornton weather in August

In August, Thornton sees average daytime highs of 83°F and overnight lows near 57°F, with 1.5 in of rain across 6.4 wet days and about 13.6 hours of daylight. It is the 2nd-warmest and 7th-wettest month of the year here.

Day-to-day highs hold fairly steady near 83°F through the month. The sky is clear or mostly clear about 40% 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 13 hours by month's end. Set against the rest of the year, August is Thornton's 7th-clearest and 12th-windiest month. For the whole year in context, see Thornton's year-round climate.

Daytime high
83°
2nd warmest
Overnight low
57°
11th coldest
Rainfall
1.5 in
6.4 wet days
Daylight
13 h 36 min
5:16 AM – 6:52 PM
Cloud cover
50%
7th clearest
Wind
5 mph
12th windiest
Solar energy
6.52 kWh/m²
Travel score
6.3
out of 10

Thornton is city in Adams and Weld counties in Colorado, United States.

Density
1,433/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 83°F through the month.

A typical August day in Thornton reaches about 83°F in the afternoon and slips back to 57°F overnight — a 27°F spread between the day's warmth and the night's chill. On most days the high lands between 75°F and 91°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)
18558
28458
38458
48458
58458
68458
78458
88458
98458
108457
118457
128457
138457
148457
158457
168357
178357
188356
198356
208356
218356
228356
238356
248356
258356
268356
278355
288255
298255
308255
318255

How August really feels in Thornton

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.

Thornton weather by month

How August compares with the rest of the year at a glance. August is the 2nd-warmest and 7th-wettest month here — the current month is highlighted below.

MonthHigh / Low (°F)Rainfall (inches)Wet daysSnow daysDaylight (hours)Travel score
Jan42° / 18°0.95.259.50.3
Feb44° / 20°0.95.85.510.41.0
Mar53° / 27°1.97.65.711.73.3
Apr59° / 33°2.79.94.7134.7
May69° / 43°3.211114.26.2
Jun80° / 52°2.18.3014.86.8
Jul85° / 58°1.67.2014.55.5
Aug83° / 57°1.56.4013.66.3
Sep76° / 49°1.45.80.512.37.7
Oct64° / 37°1.66.12.210.96.4
Nov51° / 26°1.265.19.82.9
Dec42° / 18°0.84.84.99.20.3

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 40% of the time in August.

Beyond those clear spells, partly cloudy skies cover about 27% of August, with mostly cloudy or overcast conditions the remaining 33%. Skies tend to open up as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
16139
26139
36139
46337
56436
66436
76535
86634
96634
106733
116733
126832
136832
146832
156931
166931
176931
186931
196931
206931
216733
226832
236832
246832
256931
266931
277030
287030
297129
307129
317129

Chance of precipitation in August

Any precipitation

Thornton gets around 1.5 in of rain over 6.4 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 20% and peaks near 27% on the wettest days. The odds ease toward the end of the month.

0%10%20%30%40%151015202531
Rain chance (%)
127
226
326
426
525
625
724
824
923
1023
1122
1222
1321
1421
1520
1620
1719
1819
1919
2018
2118
2217
2317
2417
2516
2616
2716
2815
2915
3015
3116

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 91% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)Humid (%)
181181
281181
383170
483170
584160
684160
785150
886140
987130
1088120
1189110
1290100
139190
149190
159280
169370
179370
189460
199460
209550
219550
229640
239640
249730
259730
269730
279730
289820
299820
309820
319820

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 13 hours by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 66 minutes over August. Sunrise moves from 5:02 AM to 5:31 AM, and sunset from 7:10 PM to 6:29 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.15:027:10
214.15:037:09
314.15:047:08
414.05:057:07
514.05:067:05
614.05:077:04
713.95:087:03
813.95:097:02
913.95:107:01
1013.85:116:59
1113.85:126:58
1213.75:136:57
1313.75:146:56
1413.75:146:54
1513.65:156:53
1613.65:166:52
1713.55:176:50
1813.55:186:49
1913.55:196:47
2013.45:206:46
2113.45:216:44
2213.35:226:43
2313.35:236:41
2413.35:246:40
2513.25:256:38
2613.25:266:37
2713.15:276:35
2813.15:286:34
2913.15:296:32
3013.05:306:30
3113.05:316:29

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 6.52 kWh/m².

For context, solar energy here swings from a low near 2.55 kWh/m² to a high of 7.45 kWh/m² in June across the year — August's 6.52 kWh/m² falls in the middle.

0246151015202531
Solar energy (kWh/m²)Level
16.8Intense
26.8Intense
36.8Intense
46.8Intense
56.8Intense
66.8Intense
76.7Intense
86.7Intense
96.7Intense
106.7Intense
116.7Intense
126.7Intense
136.6Intense
146.6Intense
156.6Intense
166.6Intense
176.5Intense
186.5Intense
196.5Intense
206.5Intense
216.4Intense
226.4Intense
236.4Intense
246.3Intense
256.3Intense
266.3Intense
276.2Intense
286.2Intense
296.2Intense
306.1Intense
316.1Intense
Planning a trip in August

Is August a good time to visit Thornton?

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

6.3
Sightseeing
4th-best month of the year
7.7
Beach & pool
1st-best month of the year

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

What to pack for Thornton in August

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

In August, Thornton sees daytime highs around 83°F and nights near 57°F. Pack light clothes and sun protection. About 6 days see rain.

light clothessun protection

UV index in Thornton 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 Thornton peaks around July 12 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near December 23 at about 2 (low).

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

025710JanFebMarAprMayJunJulAugSepOctNovDecModerateHighVery highExtremeVery highHighModerateJul 12UV 11Dec 23UV 2
UV index (midday)Level
Jan2Low
Feb4Moderate
Mar7High
Apr6High
May7Very high
Jun10Extreme
Jul11Extreme
Aug10Very high
Sep7Very high
Oct5High
Nov3Moderate
Dec2Low

Air quality in Thornton 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 Thornton is worst in August — around 21 µg/m³ PM2.5 (moderate), about 1.6× the cleanest month (May, 13 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecModerateAug 1620 µg/m³May 1113 µg/m³
PM2.5 (µg/m³)Level
Jan17Moderate
Feb15Moderate
Mar16Moderate
Apr13Moderate
May13Moderate
Jun14Moderate
Jul14Moderate
Aug21Moderate
Sep13Moderate
Oct15Moderate
Nov15Moderate
Dec16Moderate
Location & terrain

Where is Thornton?

Thornton sits at 39.9°N, 105.0°W, 5,351 ft above sea level, in United States. The nearest listed city is Northglenn, 1.2 mi away.

Topography around Thornton

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

Within 2 miles, the terrain around Thornton has only modest variations in elevation — a maximum elevation change of 472 ft around an average of 5,276 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 856 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 9,708 ft.

The land around Thornton is covered by artificial surfaces (68%) within 2 miles, artificial surfaces (45%) and grassland (34%) within 10 miles, and grassland (43%) and trees (30%) within 50 miles.

2 miles
472 ft
10 miles
856 ft
50 miles
9,708 ft
treesgrasslandcroplandartificial surfacesbare terrainwatermoss and lichen
August weather nearby: Northglenn 1.2 mi · Sherrelwood 2.5 mi · Westminster 4.3 mi · Commerce City 4.3 mi · Broomfield 6.8 mi · Arvada 7.5 mi · Denver 8.7 mi · Wheat Ridge 8.7 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 Thornton (39.868°, -104.9719°, elevation 5,351 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).