Jefferson, SD Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Jefferson, a city in Union County, South Dakota.
Overnight
66°F
Slight Chance Showers And Thunderstorms
A slight chance of showers and thunderstorms between 1am and 2am, then patchy fog and a chance of showers and thunderstorms. Mostly cloudy. Low around 66, with temperatures rising to around 70 overnight. North northwest wind around 5 mph. Chance of precipitation is 40%. New rainfall amounts between a tenth and quarter of an inch possible.
7-day forecast for Jefferson
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 66°F | Slight Chance Showers And Thunderstorms | 5 mph NNW | 35% |
| Saturday | 70°F | Chance Showers And Thunderstorms then Mostly Cloudy | 5 to 10 mph NNW | 31% |
| Saturday Night | 58°F | Cloudy then Slight Chance Rain Showers | 10 mph N | 15% |
| Sunday | 65°F | Chance Rain Showers | 10 mph NE | 30% |
| Sunday Night | 54°F | Rain Showers Likely | 5 to 10 mph ENE | 66% |
| Monday | 61°F | Rain Showers Likely | 5 to 10 mph ENE | 66% |
| Monday Night | 49°F | Chance Rain Showers then Mostly Cloudy | 5 to 10 mph ENE | 30% |
| Tuesday | 63°F | Mostly Cloudy | 5 to 10 mph E | 4% |
| Tuesday Night | 49°F | Partly Cloudy | 5 mph ESE | 0% |
| Wednesday | 67°F | Partly Sunny | 5 to 10 mph SE | 11% |
| Wednesday Night | 53°F | Mostly Cloudy then Chance Rain Showers | 5 mph SE | 35% |
| Thursday | 67°F | Chance Rain Showers | 5 to 10 mph SSE | 35% |
| Thursday Night | 55°F | Slight Chance Rain Showers | 5 mph SE | 19% |
| Friday | 69°F | Slight Chance Rain Showers then Partly Sunny | 5 to 10 mph SE | 19% |
Forecast source: National Weather Service (api.weather.gov) for Jefferson (42.604, -96.566). Updated through the day.
Growing snapshot for Jefferson
Last spring frost
Apr 29
First fall frost
Oct 7
Growing season
161 days
Hardiness zone
5a
More local growing data for Jefferson: nearby ZIP 57038 weather · frost dates · planting calendar · South Dakota frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Sioux City Ang, Ia (16.1 mi from Jefferson). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.