Lewistown weather in August: Lewistown, Montana: normal highs, lows, rain and records for August
Lewistown in August has a normal high of 81°F and a normal low of 50°F, a daily mean of 65°F, falling from 84°F on the 1st to 77°F by the 31st. Measurable precipitation falls on 9 days in a normal August, 1.69 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 27°C and low of 10°C, 43 mm of precipitation in August.
- NOAA stationLewistown Municipal Airport
- Station IDUSW00024036
- Location47.05°N 109.46°W
- Elevation4,145 ft (1,263 m)
- Population6,204
- Jan 34° 13°
- Feb 35° 14°
- Mar 44° 21°
- Apr 53° 29°
- May 63° 37°
- Jun 71° 45°
- Jul 82° 51°
- Aug 81° 50°
- Sep 70° 42°
- Oct 56° 31°
- Nov 43° 21°
- Dec 35° 14°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Lewistown in August?
The normal high is 81°F and the normal low 50°F, for a daily mean of 65.4°F. August is 0.7°F cooler than July and 9.5°F warmer than September. August is the 2nd warmest month of the year in Lewistown and the 5th wettest. Across the month the normal high falls 7°F, from 84°F on August 1 to 77°F on August 31. From one year to the next August's mean temperature typically moves about 2.6°F either way (NOAA's standard deviation), so roughly two Augusts in three average between 63°F and 68°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 30%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| August 1 | 84°F | 52°F | 30% | 13% |
| August 8 | 83°F | 52°F | 29% | 13% |
| August 15 | 82°F | 50°F | 29% | 13% |
| August 22 | 80°F | 48°F | 28% | 13% |
| August 31 | 77°F | 46°F | 28% | 13% |
Every day of August: normal high, low and chance of precipitation (warmest afternoon August 1, coldest night August 31)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| August 1 | 84°F | 52°F | 30% | 13% | 15 h |
| August 2 | 84°F | 52°F | 30% | 13% | 14 h 50 min |
| August 3 | 84°F | 52°F | 30% | 13% | 14 h 50 min |
| August 4 | 84°F | 52°F | 30% | 13% | 14 h 50 min |
| August 5 | 84°F | 52°F | 29% | 13% | 14 h 50 min |
| August 6 | 84°F | 52°F | 29% | 13% | 14 h 40 min |
| August 7 | 84°F | 52°F | 29% | 13% | 14 h 40 min |
| August 8 | 83°F | 52°F | 29% | 13% | 14 h 40 min |
| August 9 | 83°F | 51°F | 29% | 13% | 14 h 40 min |
| August 10 | 83°F | 51°F | 29% | 13% | 14 h 30 min |
| August 11 | 83°F | 51°F | 29% | 13% | 14 h 30 min |
| August 12 | 83°F | 51°F | 29% | 13% | 14 h 30 min |
| August 13 | 82°F | 51°F | 29% | 13% | 14 h 20 min |
| August 14 | 82°F | 50°F | 29% | 13% | 14 h 20 min |
| August 15 | 82°F | 50°F | 29% | 13% | 14 h 20 min |
| August 16 | 82°F | 50°F | 29% | 13% | 14 h 10 min |
| August 17 | 81°F | 50°F | 29% | 13% | 14 h 10 min |
| August 18 | 81°F | 49°F | 28% | 13% | 14 h 10 min |
| August 19 | 81°F | 49°F | 28% | 13% | 14 h 10 min |
| August 20 | 80°F | 49°F | 28% | 13% | 14 h |
| August 21 | 80°F | 49°F | 28% | 13% | 14 h |
| August 22 | 80°F | 48°F | 28% | 13% | 14 h |
| August 23 | 79°F | 48°F | 28% | 13% | 13 h 50 min |
| August 24 | 79°F | 48°F | 28% | 13% | 13 h 50 min |
| August 25 | 79°F | 48°F | 28% | 13% | 13 h 50 min |
| August 26 | 78°F | 47°F | 28% | 13% | 13 h 40 min |
| August 27 | 78°F | 47°F | 28% | 13% | 13 h 40 min |
| August 28 | 78°F | 47°F | 28% | 13% | 13 h 40 min |
| August 29 | 77°F | 46°F | 28% | 13% | 13 h 30 min |
| August 30 | 77°F | 46°F | 28% | 13% | 13 h 30 min |
| August 31 | 77°F | 46°F | 28% | 13% | 13 h 30 min |
- Normal high
- 81°FAugust average
- Normal low
- 50°FAugust average
- Precipitation
- 1.69 inmonth total
- Days with precipitation
- 90.01 inch or more
- Days at 90°F or more
- 5
- Daylight
- 15 h to 13 h 30 minAugust 1 to August 31
- Days at 70°F or more
- 27
- Days at 80°F or more
- 19
- Sunshine
- 85%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00024036; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Lewistown in August?
On a given August day the chance of 0.01 inch or more is 29% on average, highest around August 1 (30%). In all, 1.69 in falls on 9 days of a normal August.
In a normal August in Lewistown, 5 days reach 90°F.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00024036.
How humid and windy is Lewistown in August?
At 3 p.m. the normal temperature is 75°F with 26% relative humidity and a dew point of 38°F; at 6 a.m. it is 50°F with 67% humidity. The wind averages 7.6 mph, most often from the northwest in the afternoon. A dew point under 50°F feels dry.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 50°F | 39°F | 67% | 6.3 mph | – |
| 9 a.m. | 64°F | 41°F | 43% | 6.9 mph | – |
| noon | 72°F | 38°F | 29% | 8.8 mph | – |
| 3 p.m. | 75°F | 38°F | 26% | 9.8 mph | – |
| 6 p.m. | 70°F | 39°F | 33% | 8.1 mph | – |
| 9 p.m. | 58°F | 40°F | 51% | 7.7 mph | – |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00024036. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for August in Lewistown?
The warmest August temperature on this station's record (since 1896) is 103°F, on August 5, 1961; the coldest is 27°F, on August 25, 1910. The wettest August brought 6.06 in (2014).
The August mean against the 1991-2020 normal of 65.4°F: 2021 65.0°F (−0.5), 2022 69.9°F (+4.5), 2023 66.8°F (+1.4), 2024 66.0°F (+0.6), 2025 66.3°F (+0.9), 2026 66.3°F (+0.9). 5 of 6 ran warmer than normal.
| August | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 65.0°F | −0.5°F | 2.19 in |
| 2022 | 69.9°F | +4.5°F | 1.89 in |
| 2023 | 66.8°F | +1.4°F | 0.51 in |
| 2024 | 66.0°F | +0.6°F | 1.11 in |
| 2025 | 66.3°F | +0.9°F | 2.38 in |
| 2026 | 66.3°F | +0.9°F | 0.46 in |
Source: records: ACIS, station USW00024036; recent months: ACIS, station USW00024036. Records and recent months use complete months only.
How does August in Lewistown compare across Montana?
Across the 141 places PlainClimate covers in Montana, August normal highs run from 71°F in Cooke City to 90°F in Hardin; Lewistown's is 81°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.