Weather and climate in Rapid Valley, SD
What the weather is like in Rapid Valley
The warmest month in Rapid Valley is July, with average highs of 91°F. The coolest is February, when nights average 17°F. About 17.7 in of rain and snow falls in a typical year, most in May and least in January.
Skies are clearest in August (42% average cloud cover) and cloudiest in February (67%). Combining cloud with the length of truly dark nights, September, October, November offer the most clear, dark hours for stargazing.
Clear, dark hours per night
Hours of full astronomical darkness in mid-month, multiplied by the average share of clear sky. A rough guide to how much good observing time a typical night offers.
Monthly averages
| Month | High | Low | Precipitation | Cloud cover | Humidity | Wind | Dark hours |
|---|---|---|---|---|---|---|---|
| January | 38°F | 18°F | 0.3 in | 65% | 67% | 6 mph | 11.3 h |
| February | 38°F | 17°F | 0.5 in | 67% | 65% | 7 mph | 10.2 h |
| March | 50°F | 25°F | 1.0 in | 66% | 60% | 7 mph | 8.8 h |
| April | 59°F | 33°F | 2.0 in | 63% | 58% | 7 mph | 7.0 h |
| May | 70°F | 43°F | 3.4 in | 61% | 57% | 6 mph | 5.0 h |
| June | 82°F | 55°F | 2.7 in | 52% | 54% | 6 mph | 3.7 h |
| July | 91°F | 63°F | 2.2 in | 42% | 50% | 5 mph | 4.4 h |
| August | 87°F | 60°F | 1.9 in | 42% | 51% | 5 mph | 6.3 h |
| September | 77°F | 50°F | 1.5 in | 44% | 52% | 6 mph | 8.2 h |
| October | 60°F | 36°F | 1.3 in | 56% | 59% | 6 mph | 9.8 h |
| November | 48°F | 27°F | 0.5 in | 60% | 61% | 6 mph | 11.0 h |
| December | 37°F | 19°F | 0.4 in | 65% | 67% | 6 mph | 11.6 h |
Climate nearby
Climate averages: NASA POWER, 2001–2025, for the grid area around 44.00, -103.13 (about 50 km across). High and low temperatures are estimated from the monthly mean and the average daily range. Hills, coasts and cities can differ from the area average. Aurora outlook for Rapid Valley · Sources and methods.