Jefferson County Climate
Jefferson County, Idaho
Avg Annual Temp
44.8°F
Annual Precip
11.2"
Annual Snowfall
20.4"
Extreme Heat Days
21.75
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Seasonal Overview
National Comparison
Climate Profile
About Jefferson County Weather
Dry and chilly in the High Desert
Jefferson County maintains a cool annual average of 44.8°F, well below the national median. With only 11.2 inches of annual precipitation, it is significantly drier than the average American county.
Below the Idaho state temperature average
At 44.8°F, the county sits roughly 1.7 degrees cooler than the Idaho statewide average of 46.5°F. Its precipitation level of 11.2 inches is also notably lower than the state's 17-inch average.
Sharing the cold with Idaho County
Jefferson County matches Idaho County's 44.8°F average temperature exactly, despite being on the other side of the state. However, it receives less than half the annual snowfall of its western peer, totaling just 20.4 inches.
Frigid winters and arid summer days
Winter is biting with a January average of 20.5°F, which is much colder than many neighboring regions. July brings relief with a 69.2°F average, though the county still sees 22 days above 90°F.
Winterize for deep freezes
Heating systems must be robust to handle the 20°F January average, and pipes require extra insulation against the dry cold. Summer planning should account for the 22 days of extreme heat despite the generally cool annual average.
Frequently Asked Questions
What is the average temperature in Jefferson County?
How much rain does Jefferson County get?
Does it snow in Jefferson County?
How hot does Jefferson County get in summer?
How cold are winters in Jefferson County?
Track your own weather in Jefferson County
Ambient Weather personal weather stations give you hyperlocal climate data.
Sponsored
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.