Fort Thompson, SD Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Fort Thompson, a community in Buffalo County, South Dakota.
This Afternoon
48°F
Mostly Cloudy
Mostly cloudy, with a high near 48. North northwest wind 20 to 23 mph, with gusts as high as 45 mph.
7-day forecast for Fort Thompson
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 48°F | Mostly Cloudy | 20 to 23 mph NNW | 9% |
| Tonight | 35°F | Cloudy | 12 to 17 mph NW | 9% |
| Wednesday | 48°F | Chance Light Rain | 14 to 18 mph NW | 29% |
| Wednesday Night | 34°F | Mostly Cloudy | 9 to 13 mph NW | 11% |
| Thursday | 50°F | Mostly Sunny | 7 to 10 mph NNW | 0% |
| Thursday Night | 28°F | Partly Cloudy | 5 mph E | 0% |
| Friday | 49°F | Partly Sunny | 2 to 6 mph SSE | 0% |
| Friday Night | 30°F | Partly Cloudy | 3 mph S | 0% |
| Saturday | 59°F | Mostly Sunny | 3 to 10 mph WSW | 4% |
| Saturday Night | 34°F | Mostly Clear | 6 mph WNW | 1% |
| Sunday | 61°F | Sunny | 3 to 9 mph SSW | 0% |
| Sunday Night | 38°F | Mostly Clear | 8 mph SSW | 0% |
| Monday | 61°F | Sunny | 8 to 14 mph NW | 0% |
| Monday Night | 36°F | Partly Cloudy | 6 mph WNW | 0% |
Forecast source: National Weather Service (api.weather.gov) for Fort Thompson (44.055, -99.405). Updated through the day.
Growing snapshot for Fort Thompson
Last spring frost
May 6
First fall frost
Oct 5
Growing season
152 days
Hardiness zone
4b
More local growing data for Fort Thompson: nearby ZIP 57339 weather · frost dates · planting calendar · South Dakota frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Lake Sharpe Prj, Sd (4.3 mi from Fort Thompson). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.