Sinai, SD Weather & Growing Conditions
Overnight
37°F
Rain Showers Likely
Rain showers likely. Cloudy. Low around 37, with temperatures rising to around 40 overnight. Northwest wind 15 to 20 mph, with gusts as high as 30 mph. Chance of precipitation is 60%. New rainfall amounts less than a tenth of an inch possible.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 37°F | Rain Showers Likely | 15 to 20 mph NW | 60% |
| Wednesday | 43°F | Rain Showers | 20 mph NW | 78% |
| Wednesday Night | 34°F | Chance Rain Showers then Mostly Cloudy | 15 mph NNW | 54% |
| Thursday | 43°F | Mostly Cloudy | 10 to 15 mph N | 0% |
| Thursday Night | 28°F | Mostly Cloudy | 0 to 10 mph NNE | 0% |
| Friday | 43°F | Mostly Sunny | 0 to 5 mph SE | 0% |
| Friday Night | 28°F | Partly Cloudy | 5 mph S | 0% |
| Saturday | 52°F | Sunny | 5 to 10 mph SW | 0% |
| Saturday Night | 33°F | Mostly Clear | 5 to 10 mph W | 0% |
| Sunday | 54°F | Sunny | 5 to 10 mph WSW | 0% |
| Sunday Night | 37°F | Mostly Clear | 5 to 10 mph SSW | 0% |
| Monday | 58°F | Sunny | 10 mph W | 0% |
| Monday Night | 36°F | Mostly Clear | 5 mph NW | 0% |
| Tuesday | 56°F | Mostly Sunny | 5 mph W | 1% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Sinai, SD
Last spring frost
May 3
First fall frost
Oct 2
Growing season
151 days
Hardiness zone
4b
Explore more for Sinai, SD: full frost dates · planting calendar · South Dakota frost dates
Climate data from the nearest NOAA station, Arlington 1 W, Sd (10.3 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.