Great Falls weather in August

In August, Great Falls sees average daytime highs of 83°F and overnight lows near 55°F, with 1.1 in of rain across 4.8 wet days and about 14.1 hours of daylight. It is the 2nd-warmest and 6th-wettest month of the year here.

Highs ease over the month, from about 85°F in the first days to 79°F by the end. The sky is clear or mostly clear about 54% of the time in August, and the air most often feels dry.

Daylight stretches from about 14 h 48 min at the start of August to 13 h 18 min by month's end. Set against the rest of the year, August is Great Falls's 2nd-clearest and 12th-windiest month. For the whole year in context, see Great Falls's year-round climate.

Daytime high
83°
2nd warmest
Overnight low
55°
11th coldest
Rainfall
1.1 in
4.8 wet days
Daylight
14 h 06 min
5:27 AM – 7:32 PM
Cloud cover
39%
2nd clearest
Wind
6 mph
12th windiest
Solar energy
6.32 kWh/m²
Travel score
7.0
out of 10

Great Falls is city in and county seat of Cascade County, Montana, United States.

Density
985/km²
people per km²
Founded
1883

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 85°F in the first days to 79°F by the end.

A typical August day in Great Falls reaches about 83°F in the afternoon and slips back to 55°F overnight — a 28°F spread between the day's warmth and the night's chill. On most days the high lands between 70°F and 93°F. Set against its neighbours, August runs on par with July and about 12°F warmer than September.

40°60°80°151015202531
Avg high (°F)Avg low (°F)
18557
28557
38557
48557
58557
68557
78457
88456
98456
108456
118456
128356
138356
148355
158355
168355
178355
188255
198255
208254
218254
228254
238154
248154
258153
268053
278053
288053
297952
307952
317852

How August really feels in Great Falls

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.

Great Falls 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
Jan33° / 18°0.85.75.78.70.0
Feb36° / 19°0.75.85.99.90.0
Mar45° / 26°1.075.311.61.2
Apr55° / 34°2.09.44.213.33.5
May65° / 43°2.410.81.114.95.7
Jun73° / 50°2.910.50.115.76.6
Jul84° / 56°0.95.1015.46.5
Aug83° / 55°1.14.8014.17.0
Sep71° / 47°1.46.30.212.47.3
Oct57° / 37°1.372.510.64.3
Nov43° / 27°0.95.84.79.10.7
Dec34° / 20°0.85.75.68.30.0

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 54% of the time in August.

Beyond those clear spells, partly cloudy skies cover about 21% of August, with mostly cloudy or overcast conditions the remaining 25%. Skies tend to cloud over as the month goes on.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
17921
27921
37921
47723
57723
67723
77723
87624
97624
107525
117525
127525
137525
147525
157426
167426
177426
187426
197525
207525
217426
227426
237525
247426
257426
267327
277327
287228
297228
307129
317129

Chance of precipitation in August

Any precipitation

Great Falls gets around 1.1 in of rain over 4.8 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 16% and peaks near 17% on the wettest days.

0%10%20%30%151015202531
Rain chance (%)
113
213
313
413
514
614
714
814
915
1015
1115
1216
1316
1416
1516
1617
1717
1817
1917
2017
2117
2217
2317
2417
2516
2616
2716
2817
2917
3017
3117

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 99% of days. It rarely turns muggy — the humid and sticky bands barely register.

0%25%50%75%100%151015202531
Dry (%)Comfortable (%)
1982
2982
3982
4982
5982
6982
7982
8982
9982
10982
11982
12982
13982
14982
15982
16991
17991
18991
19991
20991
21991
22991
23991
24991
25991
26991
27991
28991
29991
30991
31991

Wind in August

Winds average 6 mph in August, the calmest month.

Across August, daily wind ranges from about 6 mph on the calmest days to 7 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
16calm
26calm
36calm
46calm
56calm
66calm
76calm
86calm
96calm
106calm
116calm
126calm
136calm
146calm
156calm
166calm
176calm
186calm
196calm
206calm
216calm
226calm
237calm
247calm
257calm
267calm
277calm
287calm
297calm
307calm
317calm

Sunrise & sunset in August

DaylightNight

Daylight runs from about 14 h 48 min at the start of August to 13 h 18 min by month's end. The lit band spans sunrise to sunset each day.

Days shrink by about 90 minutes over August. Sunrise moves from 5:07 AM to 5:47 AM, and sunset from 7:56 PM to 7:03 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.85:077:56
214.85:087:54
314.75:107:53
414.75:117:51
514.65:127:50
614.65:137:48
714.55:157:47
814.55:167:45
914.45:177:44
1014.45:197:42
1114.35:207:40
1214.35:217:39
1314.25:237:37
1414.25:247:35
1514.15:257:34
1614.15:277:32
1714.05:287:30
1814.05:307:28
1913.95:317:26
2013.95:327:25
2113.85:347:23
2213.85:357:21
2313.75:367:19
2413.75:387:17
2513.65:397:15
2613.55:407:13
2713.55:427:11
2813.45:437:09
2913.45:457:07
3013.35:467:05
3113.35:477:03

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 6.32 kWh/m².

For context, solar energy here swings from a low near 1.39 kWh/m² to a high of 7.32 kWh/m² in July across the year — August's 6.32 kWh/m² sits near the top of that range.

0246151015202531
Solar energy (kWh/m²)Level
17.0Intense
26.9Intense
36.9Intense
46.8Intense
56.8Intense
66.8Intense
76.7Intense
86.7Intense
96.6Intense
106.6Intense
116.5Intense
126.5Intense
136.5Intense
146.4Intense
156.4Intense
166.3Intense
176.3Intense
186.2Intense
196.2Intense
206.2Intense
216.1Intense
226.1Intense
236.0Intense
246.0Bright
255.9Bright
265.9Bright
275.8Bright
285.8Bright
295.7Bright
305.6Bright
315.6Bright
Planning a trip in August

Is August a good time to visit Great Falls?

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

7.0
Sightseeing
2nd-best month of the year
7.9
Beach & pool
2nd-best month of the year

August is one of the better times to visit Great Falls for general sightseeing. The water and warmth also suit a beach or pool day.

What to pack for Great Falls in August

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

In August, Great Falls sees daytime highs around 83°F and nights near 55°F. Pack light clothes and sun protection. About 5 days see rain.

light clothessun protection

UV index in Great Falls in August

LowModerateHighVery highExtreme

Clear-sky midday UV in August peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.

Under clear skies, the midday UV index in Great Falls peaks around July 14 at about 8 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 17 at about 1 (low).

The index reaches 3 or more — the level where the WHO recommends sun protection — in 8 months of the year.

025710JanFebMarAprMayJunJulAugSepOctNovDecLowModerateHighVery highHighModerateLowJul 14UV 8Dec 17UV 1
UV index (midday)Level
Jan1Low
Feb2Low
Mar3Moderate
Apr4Moderate
May7High
Jun7Very high
Jul8Very high
Aug6High
Sep5Moderate
Oct4Moderate
Nov1Low
Dec1Low

Air quality in Great Falls 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 Great Falls is worst in August — around 23 µg/m³ PM2.5 (moderate), about 3.8× the cleanest month (December, 6 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodModerateGoodAug 1323 µg/m³Dec 106 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb6Good
Mar11Good
Apr13Moderate
May12Good
Jun9Good
Jul20Moderate
Aug23Moderate
Sep16Moderate
Oct8Good
Nov6Good
Dec6Good
Location & terrain

Where is Great Falls?

Great Falls sits at 47.5°N, 111.3°W, 3,330 ft above sea level, in United States. The nearest listed city is Helena, 71 mi away.

Topography around Great Falls

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

Within 2 miles, the terrain around Great Falls has only modest variations in elevation — a maximum elevation change of 217 ft around an average of 3,366 ft above sea level; within 10 miles, significant variations in elevation — a maximum elevation change of 1,270 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 6,588 ft.

The land around Great Falls is covered by artificial surfaces (52%) and grassland (22%) within 2 miles, grassland (51%) and cropland (38%) within 10 miles, and grassland (55%) and cropland (31%) within 50 miles.

2 miles
217 ft
10 miles
1,270 ft
50 miles
6,588 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
August weather nearby: Helena 71 mi · Butte 119 mi · Bozeman 126 mi · Missoula 134 mi · Kalispell 148 mi · Whitefish 154 mi · Lethbridge 167 mi · Medicine Hat 178 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 Great Falls (47.5002°, -111.3008°, elevation 3,330 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).