Average Soil Temperature in Spearfish, SD — January 2026
Data from Sundance 8 NNW (28.4 mi away) • 31 of 31 days reported
Monthly Summary by Depth
2" depth
32.3°F
avg
30.9°F – 34.3°F
31 days
4" depth
32.5°F
avg
31.3°F – 34.7°F
31 days
8" depth
33.4°F
avg
32°F – 34.9°F
31 days
20" depth
34.9°F
avg
33.6°F – 36°F
31 days
40" depth
37°F
avg
35.8°F – 38.3°F
31 days
Daily Readings
| Date | 2" | 4" | 8" | 20" | 40" |
|---|---|---|---|---|---|
| Jan 1 | 32.4°F | 32.4°F | 33.8°F | 35.8°F | 38.3°F |
| Jan 2 | 32.5°F | 32.5°F | 33.8°F | 35.6°F | 38.1°F |
| Jan 3 | 32.9°F | 32.9°F | 34°F | 35.6°F | 37.9°F |
| Jan 4 | 33.6°F | 34.3°F | 34.5°F | 35.6°F | 37.8°F |
| Jan 5 | 34.3°F | 34.7°F | 34.9°F | 35.8°F | 37.8°F |
| Jan 6 | 33.6°F | 33.8°F | 34.9°F | 36°F | 37.8°F |
| Jan 7 | 33.1°F | 33.6°F | 34.5°F | 35.8°F | 37.8°F |
| Jan 8 | 32.9°F | 33.3°F | 34.3°F | 35.8°F | 37.8°F |
| Jan 9 | 32.9°F | 33.1°F | 34.2°F | 35.6°F | 37.6°F |
| Jan 10 | 32.7°F | 32.7°F | 34°F | 35.4°F | 37.6°F |
| Jan 11 | 32.5°F | 32.7°F | 33.8°F | 35.4°F | 37.4°F |
| Jan 12 | 32.5°F | 32.7°F | 33.8°F | 35.2°F | 37.2°F |
| Jan 13 | 33.1°F | 33.4°F | 34°F | 35.2°F | 37.2°F |
| Jan 14 | 33.3°F | 33.6°F | 34.3°F | 35.2°F | 37.2°F |
| Jan 15 | 33.4°F | 33.6°F | 34.3°F | 35.2°F | 37.2°F |
| Jan 16 | 33.1°F | 33.1°F | 34.2°F | 35.2°F | 37.2°F |
| Jan 17 | 32.5°F | 32.7°F | 33.8°F | 35.2°F | 37.2°F |
| Jan 18 | 32.4°F | 32.5°F | 33.4°F | 35.1°F | 37°F |
| Jan 19 | 32.2°F | 32.2°F | 33.3°F | 34.9°F | 37°F |
| Jan 20 | 32°F | 32°F | 33.1°F | 34.7°F | 36.9°F |
| Jan 21 | 31.8°F | 32°F | 32.9°F | 34.5°F | 36.7°F |
| Jan 22 | 31.6°F | 31.8°F | 32.7°F | 34.3°F | 36.7°F |
| Jan 23 | 31.5°F | 31.6°F | 32.7°F | 34.3°F | 36.5°F |
| Jan 24 | 31.3°F | 31.5°F | 32.5°F | 34.2°F | 36.3°F |
| Jan 25 | 31.1°F | 31.3°F | 32.4°F | 34°F | 36.3°F |
| Jan 26 | 30.9°F | 31.3°F | 32.2°F | 34°F | 36.1°F |
| Jan 27 | 31.1°F | 31.3°F | 32.2°F | 33.8°F | 36°F |
| Jan 28 | 31.1°F | 31.3°F | 32°F | 33.6°F | 36°F |
| Jan 29 | 31.3°F | 31.3°F | 32°F | 33.6°F | 36°F |
| Jan 30 | 31.3°F | 31.5°F | 32.2°F | 33.6°F | 35.8°F |
| Jan 31 | 31.5°F | 31.5°F | 32°F | 33.6°F | 35.8°F |