Spearfish Weather in August
Average highs run from 85°F on August 1 to 80°F on August 31, and lows from 58°F to 53°F. Normal precipitation for the month is 1.88 in over about 7 wet days.
August day by day
The normal high and low for each date, and the record, in °F.
- Normal low
- Normal high
- Record high
- Record low
August at a glance
- Average high
- 83°F
- Average low
- 56°F
- Precipitation
- 1.88 in
- Record high
- 104°FAug 1, 1900
- Record low
- 32°FAug 26, 1906
- Chance of a freeze
- 0%
- Days of 90°F or more
- 8.5
- Daylight
- 14 h 38 min to 13 h 16 min
- Cloud cover
- 45%
- Humidity
- 51%
- Dew point
- 49°F
- Wind
- 7.2 mph
Every day of the month
A wet day has at least 0.01 inch of precipitation; snow means at least 0.1 inch of snowfall.
| Date | Normal high | Normal low | Record high | Record low | Chance wet | Chance of snow |
|---|---|---|---|---|---|---|
| Aug 1 | 85°F | 58°F | 104°F 1900 | 42°F 1920 | 27% | 0% |
| Aug 2 | 85°F | 58°F | 102°F 1938 | 43°F 2018 | 27% | 0% |
| Aug 3 | 85°F | 58°F | 104°F 1934 | 39°F 1978 | 27% | 0% |
| Aug 4 | 85°F | 58°F | 104°F 1941 | 41°F 1952 | 26% | 0% |
| Aug 5 | 84°F | 58°F | 103°F 1941 | 39°F 1906 | 26% | 0% |
| Aug 6 | 84°F | 58°F | 100°F 1893 | 41°F 1906 | 26% | 0% |
| Aug 7 | 84°F | 58°F | 101°F 1949 | 42°F 1985 | 25% | 0% |
| Aug 8 | 84°F | 58°F | 104°F 1975 | 41°F 1906 | 25% | 0% |
| Aug 9 | 84°F | 58°F | 102°F 1958 | 41°F 1917 | 25% | 0% |
| Aug 10 | 84°F | 57°F | 103°F 1935 | 33°F 1917 | 25% | 0% |
| Aug 11 | 84°F | 57°F | 103°F 2000 | 40°F 1902 | 24% | 0% |
| Aug 12 | 84°F | 57°F | 104°F 1938 | 38°F 1920 | 24% | 0% |
| Aug 13 | 84°F | 57°F | 102°F 1893 | 40°F 1966 | 24% | 0% |
| Aug 14 | 83°F | 57°F | 101°F 1935 | 44°F 1985 | 23% | 0% |
| Aug 15 | 83°F | 57°F | 101°F 1929 | 47°F 1966 | 23% | 0% |
| Aug 16 | 83°F | 56°F | 98°F 1906 | 45°F 1893 | 23% | 0% |
| Aug 17 | 83°F | 56°F | 100°F 1959 | 40°F 1944 | 23% | 0% |
| Aug 18 | 83°F | 56°F | 101°F 1959 | 41°F 1985 | 22% | 0% |
| Aug 19 | 83°F | 56°F | 101°F 1948 | 41°F 1920 | 22% | 0% |
| Aug 20 | 83°F | 56°F | 100°F 1986 | 37°F 1920 | 22% | 0% |
| Aug 21 | 82°F | 55°F | 99°F 1894 | 39°F 1951 | 22% | 0% |
| Aug 22 | 82°F | 55°F | 102°F 2010 | 39°F 1966 | 21% | 0% |
| Aug 23 | 82°F | 55°F | 102°F 1937 | 38°F 1966 | 21% | 0% |
| Aug 24 | 82°F | 55°F | 98°F 1976 | 36°F 1910 | 21% | 0% |
| Aug 25 | 82°F | 54°F | 99°F 2000 | 37°F 1910 | 21% | 0% |
| Aug 26 | 81°F | 54°F | 102°F 1926 | 32°F 1906 | 21% | 0% |
| Aug 27 | 81°F | 54°F | 101°F 1937 | 39°F 1906 | 21% | 0% |
| Aug 28 | 81°F | 54°F | 99°F 1924 | 33°F 1911 | 21% | 0% |
| Aug 29 | 81°F | 53°F | 99°F 1950 | 37°F 1920 | 21% | 0% |
| Aug 30 | 80°F | 53°F | 101°F 1948 | 33°F 1920 | 21% | 0% |
| Aug 31 | 80°F | 53°F | 102°F 1954 | 37°F 1908 | 20% | 0% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (MDT).
- August 1
- sunrise 5:42 AM, sunset 8:20 PM
- August 31
- sunrise 6:17 AM, sunset 7:33 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00397882 (Spearfish), public domain. Records: NOAA GHCN-Daily, station USC00397882, every year on file, quality-flagged values removed. Cloud, humidity, wind and sunshine: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.