Great Falls, MT weather in August
August in Great Falls: warm, with some rain. Highs 83°F, lows 50°F, rain on about 7 days. This is the peak of the warm season in Great Falls. A good month for most outdoor plans.
- Normal high
- 83°F
- Normal low
- 50°F
- Wet days
- 7
- 1.2 in total
- Muggy days
- 0
- dew point 65°F+
How August changes from start to finish
| August 1 | August 31 | |
|---|---|---|
| Normal high | 87°F | 78°F |
| Normal low | 53°F | 47°F |
| Chance of a wet day | 21% | 23% |
| Sunrise / sunset | 6:03 am / 8:59 pm | 6:42 am / 8:08 pm |
| Daylight | 14.9 h | 13.4 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Mountain Time).
A typical August day
- 6 am54°Fdew point 43°F
- 9 am68°Fdew point 44°F
- Noon77°Fdew point 42°F
- 3 pm81°Fdew point 39°F
- 6 pm78°Fdew point 40°F
- 9 pm66°Fdew point 42°F
NOAA hourly normals (local standard time) from Great Falls Intl Airport (4 mi away); average wind 9 mph; clear or few clouds in 76% of daytime hours, mostly cloudy or overcast in 16%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F9 of 31
- Hot dayshigh 90°F or more9 of 31
- Muggy daysdaily mean dew point 65°F or more0 of 31
- Wet daysat least 0.01 in of rain or melted snow7 of 31
- Notable rainat least 0.10 in3 of 31
- Freezing nightslow 32°F or below0 of 31
- Snow on the groundsnow depth 1 in or more0 of 31
Average days per August, counted from daily records for each year 1991-2020.
Rain and snow in August
Normal precipitation is 1.2 in; a dry August brings about 0.4 in and a wet one about 1.6 in (25th and 75th percentiles). About 1 day brings half an inch or more. Normal snowfall is 0.3 in.
How August varies from year to year
- Warmest August, 1991-20202001: average high 88°F
- Coolest August1993: average high 73°F
- Wettest August2014: 4.4 in
- Driest August2017: 0.06 in
- Highest reading102°F (August 10, 2018)
- Lowest reading30°F (August 24, 1992)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
August compared with July and September
| July | August | September | |
|---|---|---|---|
| Normal high | 84°F | 83°F | 72°F |
| Normal low | 51°F | 50°F | 43°F |
| Wet days | 7 | 7 | 7 |
| Comfortable days | 9 | 9 | 14 |
| Daylight | 15.5 h | 14.2 h | 12.6 h |
Highs change by -1°F from July and -11°F into September.
Nearby alternatives in August
- Cooler: Big Sky, MT153 mi · high 77°F · 11 wet days
How Great Falls ranks in August
- Normal high248th warmest of 378 cities; 3rd of 6 in Montana
- Wet days135th driest of 378
- Comfortable days76th most of 341
What to pack for Great Falls in August
- Layers – afternoons near 83°F but nights near 50°F
- Sunglasses and sunscreen – about 14.2 hours of daylight and highs near 83°F
Heating and cooling
August has 66 heating degree days and 120 cooling degree days (base 65°F), 2% of the year's total heating and cooling demand.
Questions
How hot is Great Falls in August?
The normal high is 83°F and the normal low is 50°F. From 1991 to 2020 the hottest August reading was 102°F (most recently on August 10, 2018).
Does it rain a lot in Great Falls in August?
About 7 days in August have at least 0.01 in of precipitation, and the normal total is 1.2 in. The wettest August in 1991-2020 was in 2014 (4.4 in); the driest was in 2017 (0.06 in).
Does it snow in Great Falls in August?
Yes. Normal snowfall in August is 0.3 in.
Is August a good time to visit Great Falls?
August ranks 5th of 12 months on our comfort score for Great Falls (61 out of 100). It has about 9 comfortable days and about 9 days at 90°F or hotter. The best month is June.
Where the numbers come from
- Temperature, rain, snowfall, snow depth, frost dates, humidity and wind by hour and cloud cover: Great Falls Intl Airport (USW00024143), 4.2 mi WSW of the city center, 3,664 ft (335 ft higher than the city). NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Great Falls International Airport (727750-24143), 4.3 mi WSW of the city center, 3,667 ft (338 ft higher than the city). Hourly observations, 1991-2020.