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Jefferson County Climate

Jefferson County, Oregon

NOAA NCEI 1991-2020 Climate Normals
JanFebMarAprMayJunJulAugSepOctNovDec48.5°AVG °F

Avg Annual Temp

48.5°F

Annual Precip

11.9"

Annual Snowfall

13.2"

Extreme Heat Days

35

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Dry
Wet= snowfall
1.3"
1.2"
1.0"
1.2"
1.4"
0.9"
0.4"
0.3"
0.4"
1.0"
1.3"
1.5"
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Growing Season & Gardening

USDA Hardiness Zone

7a

Minimum winter temperature range for plant survival

Growing Degree Days

1,968

Favors cool-season crops

Last spring frost (32°F): 05/22
First fall frost (32°F): 10/07

Seasonal Overview

Comfort ZoneSpring41°53°3.5"Summer60°68°1.6"Fall39°60°2.8"Winter32°36°4.0"20°40°60°80°100°

National Comparison

Warmer than 25% of US counties
Wetter than 3% of US counties
More seasonal variation than 13% of US counties

7-Day Outlook

Forecast

Current Conditions

Air Quality

Safety

Weather Alerts

Climate Advisory: Jefferson County

Climate Verdict

Jefferson County has a cool, averaging 48.5°F annually, arid conditions receiving just 11.9 inches of precipitation annually, occasional hot days — 34.739999999999995 per year above 90°F, light snow averaging 13.2 inches per year. This climate profile shapes everything from energy costs to outdoor recreation opportunities.

Seasonal Breakdown

Winters are cold, with January averaging 33.6°F. summers are pleasantly cool with July averaging 67.5°F. The 34°F seasonal variation provides noticeable but manageable change. December is typically the coldest month and July the warmest.

Outdoor & Gardening Guidance

Growing season and gardening data is currently limited for Jefferson County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.

Regional Context

Jefferson County closely matches the Oregon statewide average temperature of 50.5°F, it is also noticeably drier, receiving 25.5 inches less precipitation than the state average.

Climate Profile

About Jefferson County Weather

Cool and Arid Interior Climate

Jefferson County's annual average temperature of 48.5°F is cooler than the national median. It is a very dry region, with just 11.9 inches of annual precipitation.

Drier than the Oregon Average

The county's temperature of 48.5°F sits just below the state average of 50.5°F. Its rainfall is significantly lower than the state's 37.4-inch average, totaling only 11.9 inches.

Warmer than Neighboring Deschutes

Jefferson is slightly warmer than its neighbor Deschutes County, which averages 46.0°F. Both counties share a similarly dry profile, receiving less than 14 inches of rain annually.

Hot Summers and Light Snow

The county experiences 35 extreme heat days above 90°F, with a July average of 67.5°F. Winter is cold but relatively light on precipitation, seeing only 13.2 inches of annual snowfall.

Focus on Cooling and Irrigation

Reliable air conditioning is necessary to handle the 35 days of extreme summer heat. Because of the low 11.9-inch annual rainfall, residents should plan for water-efficient landscaping and garden irrigation.

Frequently Asked Questions

What is the average temperature in Jefferson County?
The average annual temperature in Jefferson County, OR is 48.5°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does Jefferson County get?
Jefferson County receives an average of 11.9 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 Jefferson County?
Yes, Jefferson County receives an average of 13.2 inches of snowfall per year according to NOAA climate normals.
How hot does Jefferson County get in summer?
The average summer temperature (June-August) in Jefferson County is 64.7°F. The county experiences an average of 35 days per year above 90°F.
How cold are winters in Jefferson County?
The average winter temperature (December-February) in Jefferson County is 33.8°F. January, typically the coldest month, averages 33.6°F.

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Data sources: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020. Forecast and alert data from National Weather Service API. Air quality data from Open-Meteo.

Climate normals are 30-year averages of weather variables. Station data is aggregated to county level. Forecasts and alerts are fetched live and may change frequently. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.

By Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, Data Editor
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