Union County Climate
Union County, South Dakota
Avg Annual Temp
46.9°F
Annual Precip
29.7"
Annual Snowfall
33.8"
Extreme Heat Days
17.2
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
DryWet❄= snowfall
❄0.8"
❄0.8"
❄1.7"
❄3.2"
❄4.3"
4.6"
3.0"
3.6"
3.0"
❄2.5"
❄1.2"
❄1.0"
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Seasonal Overview
National Comparison
Warmer than 20% of US counties
Wetter than 26% of US counties
More seasonal variation than 93% of US counties
Frequently Asked Questions
What is the average temperature in Union County?
The average annual temperature in Union County, SD is 46.9°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does Union County get?
Union County receives an average of 29.7 inches of precipitation per year, including both rain and meltwater from snow. This is based on NOAA 30-year climate normals.
Does it snow in Union County?
Yes, Union County receives an average of 33.8 inches of snowfall per year according to NOAA climate normals.
How hot does Union County get in summer?
The average summer temperature (June-August) in Union County is 71.1°F. The county experiences an average of 17.2 days per year above 90°F.
How cold are winters in Union County?
The average winter temperature (December-February) in Union County is 20.5°F. January, typically the coldest month, averages 17.3°F.
Track your own weather in Union County
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Data source: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020.
Climate normals are 30-year averages of weather variables computed from 1991 to 2020. Station data is aggregated to county level using spatial averaging. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.