Helena weather in August

In August, Helena sees average daytime highs of 78°F and overnight lows near 49°F, with 1.5 in of precipitation across 7.5 wet days and about 14 hours of daylight. It is the 2nd-warmest and 7th-wettest month of the year here.

Highs ease over the month, from about 80°F in the first days to 75°F by the end. The sky is clear or mostly clear about 50% of the time in August, and the air most often feels dry.

Daylight stretches from about 14 h 42 min at the start of August to 13 h 12 min by month's end. Set against the rest of the year, August is Helena's 2nd-clearest and 12th-windiest month. For the whole year in context, see Helena's year-round climate.

Daytime high
78°
2nd warmest
Overnight low
49°
11th coldest
Precipitation
1.5 in
7.5 wet days
Daylight
14 hours
5:32 AM – 7:33 PM
Cloud cover
41%
2nd clearest
Wind
4 mph
12th windiest
Solar energy
6.43 kWh/m²
Travel score
7.4
out of 10

Helena is capital city of the U.S. state of Montana and seat of Lewis and Clark County.

Density
749/km²
people per km²
Founded
1864

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 80°F in the first days to 75°F by the end.

A typical August day in Helena reaches about 78°F in the afternoon and slips back to 49°F overnight — a 29°F spread between the day's warmth and the night's chill. On most days the high lands between 66°F and 87°F. Set against its neighbours, August runs on par with July and about 11°F warmer than September.

40°60°80°151015202531
Avg high (°F)Avg low (°F)
18051
28051
38051
48051
58051
68051
78051
88051
98051
107950
117950
127950
137950
147950
157850
167849
177849
187849
197849
207849
217749
227749
237748
247648
257648
267648
277648
287547
297547
307547
317447

How August really feels in Helena

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.

Helena 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
Jan28° / 12°0.977.68.80.0
Feb31° / 13°0.977.6100.0
Mar39° / 20°1.49.77.711.60.1
Apr48° / 28°2.411.97.213.31.7
May59° / 37°3.213.82.714.84.0
Jun67° / 44°3.813.50.615.65.7
Jul78° / 50°1.78.8015.27.2
Aug78° / 49°1.57.50.1147.4
Sep67° / 42°1.66.80.912.46.7
Oct52° / 32°1.58.33.810.72.9
Nov37° / 21°1.27.76.29.20.1
Dec27° / 12°1.17.37.88.40.0

Cloud cover in August

ClearMostly clearPartly cloudyMostly cloudyOvercast

The sky is clear or mostly clear about 50% of the time in August.

Beyond those clear spells, partly cloudy skies cover about 23% of August, with mostly cloudy or overcast conditions the remaining 27%.

0%25%50%75%100%151015202531
Clearer (%)Cloudier (%)
17822
27822
37723
47624
57624
67624
77525
87426
97426
107426
117426
127327
137327
147327
157228
167228
177228
187228
197228
207228
217228
227228
237228
247228
257228
267129
277129
287129
297030
307030
317030

Chance of precipitation in August

Any precipitation

Helena gets around 1.5 in of rain and snow over 7.5 wet days in August. The line is the day-by-day chance of measurable precipitation.

Day to day, the chance of measurable precipitation averages around 24% and peaks near 27% on the wettest days, and about 0 day brings snow.

0%10%20%30%40%151015202531
Rain chance (%)
124
224
324
424
524
624
724
824
924
1025
1125
1225
1326
1426
1526
1627
1727
1827
1927
2026
2126
2225
2325
2424
2524
2623
2722
2822
2921
3021
3121

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
4991
5991
6991
7991
8991
9991
10991
11991
12991
13991
14991
15991
16991
17991
18991
19991
20991
21991
22991
23991
24991
25991
26991
27991
28991
29991
30991
31991

Wind in August

Winds average 4 mph in August, the calmest month.

Across August, daily wind ranges from about 4 mph on the calmest days to 5 mph at its breeziest. It stays fairly steady from day to day.

0246810151015202531
Wind speed (mph)Feels
14calm
24calm
34calm
44calm
54calm
64calm
74calm
84calm
94calm
104calm
114calm
124calm
134calm
144calm
154calm
164calm
174calm
184calm
194calm
204calm
214calm
224calm
234calm
244calm
255calm
265calm
275calm
285calm
295calm
305calm
315calm

Sunrise & sunset in August

DaylightNight

Daylight runs from about 14 h 42 min at the start of August to 13 h 12 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 5:13 AM to 5:51 AM, and sunset from 7:56 PM to 7:05 PM.

12 AM4 AM8 AM12 PM4 PM8 PM12 AM151015202531
Daylight (h)Sunrise (AM)Sunset (PM)
114.75:137:56
214.75:147:54
314.65:157:53
414.65:167:52
514.55:187:50
614.55:197:49
714.55:207:47
814.45:217:46
914.45:237:44
1014.35:247:43
1114.35:257:41
1214.25:277:39
1314.25:287:38
1414.15:297:36
1514.15:307:34
1614.05:327:33
1714.05:337:31
1813.95:347:29
1913.95:367:27
2013.85:377:26
2113.85:387:24
2213.75:407:22
2313.75:417:20
2413.65:427:18
2513.55:447:16
2613.55:457:15
2713.45:467:13
2813.45:487:11
2913.35:497:09
3013.35:507:07
3113.25:517:05

Solar energy in August

Daily solar energy (kWh/m²)

Average shortwave solar energy reaching the ground each day in August, about 6.43 kWh/m².

For context, solar energy here swings from a low near 1.55 kWh/m² to a high of 7.45 kWh/m² in July across the year — August's 6.43 kWh/m² sits near the top of that range.

02468151015202531
Solar energy (kWh/m²)Level
17.1Intense
27.0Intense
37.0Intense
47.0Intense
56.9Intense
66.9Intense
76.8Intense
86.8Intense
96.7Intense
106.7Intense
116.7Intense
126.6Intense
136.6Intense
146.5Intense
156.5Intense
166.4Intense
176.4Intense
186.3Intense
196.3Intense
206.3Intense
216.2Intense
226.2Intense
236.1Intense
246.1Intense
256.0Intense
266.0Bright
275.9Bright
285.9Bright
295.8Bright
305.8Bright
315.7Bright
Planning a trip in August

Hazard calendar for Helena

In seasonPeak

None of Helena's seasonal hazards are active in August. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.

Helena's rainy season runs April–June, when most of the year's rain falls.

Rainy season
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Is August a good time to visit Helena?

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

7.4
Sightseeing
1st-best month of the year
6.9
Beach & pool
1st-best month of the year

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

What to pack for Helena in August

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

In August, Helena sees daytime highs around 78°F and nights near 49°F. Pack sun protection. Worth having: light clothes. About 8 days see rain.

sun protectionlight clothes

UV index in Helena 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 Helena peaks around July 15 at about 9 (very high) — sunscreen, a hat and midday shade are essential. It bottoms out near December 21 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 15UV 9Dec 21UV 1
UV index (midday)Level
Jan1Low
Feb2Low
Mar5Moderate
Apr5Moderate
May7High
Jun8Very high
Jul9Very high
Aug7Very high
Sep5High
Oct3Moderate
Nov2Low
Dec1Low

Air quality in Helena 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 Helena is worst in August — around 25 µg/m³ PM2.5 (moderate), about 3.1× the cleanest month (December, 8 µg/m³).

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

0102030JanFebMarAprMayJunJulAugSepOctNovDecGoodModerateGoodAug 1225 µg/m³Dec 178 µg/m³
PM2.5 (µg/m³)Level
Jan9Good
Feb9Good
Mar11Good
Apr11Good
May11Good
Jun9Good
Jul23Moderate
Aug25Moderate
Sep17Moderate
Oct8Good
Nov9Good
Dec8Good
Location & terrain

Where is Helena?

Helena sits at 46.6°N, 112.0°W, 4,058 ft above sea level, in United States. The nearest listed city is Butte, 47 mi away.

Topography around Helena

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

Within 2 miles, the terrain around Helena has significant variations in elevation — a maximum elevation change of 1,588 ft around an average of 4,219 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 3,481 ft; within 50 miles, very significant variations in elevation — a maximum elevation change of 6,729 ft.

The land around Helena is covered by artificial surfaces (45%), trees (28%) and grassland (25%) within 2 miles, grassland (53%) and trees (31%) within 10 miles, and grassland (53%) and trees (42%) within 50 miles.

2 miles
1,588 ft
10 miles
3,481 ft
50 miles
6,729 ft
treesgrasslandcroplandartificial surfacesbare terrainwater
August weather nearby: Butte 47 mi · Great Falls 71 mi · Bozeman 79 mi · Missoula 94 mi · Kalispell 153 mi · Whitefish 165 mi · Billings 178 mi · Rexburg 191 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 Helena (46.5927°, -112.0361°, elevation 4,058 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).