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Siskiyou County Climate

Siskiyou County, California

NOAA NCEI 1991-2020 Climate Normals
JanFebMarAprMayJunJulAugSepOctNovDec51.5°AVG °F

Avg Annual Temp

51.5°F

Annual Precip

22.8"

Annual Snowfall

16.4"

Extreme Heat Days

48

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Dry
Wet= snowfall
3.6"
3.2"
2.9"
1.7"
1.5"
0.8"
0.3"
0.3"
0.4"
1.3"
2.6"
4.1"
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Growing Season & Gardening

USDA Hardiness Zone

8a

Minimum winter temperature range for plant survival

Growing Degree Days

2,520

Supports most vegetables & fruits

Last spring frost (32°F): 05/12
First fall frost (32°F): 10/08

Seasonal Overview

Comfort ZoneSpring43°56°6.2"Summer63°71°1.5"Fall41°63°4.3"Winter35°39°10.9"20°40°60°80°100°

National Comparison

Warmer than 37% of US counties
Wetter than 18% of US counties
More seasonal variation than 16% of US counties

7-Day Outlook

Forecast

Current Conditions

Air Quality

Safety

Weather Alerts

Climate Advisory: Siskiyou County

Climate Verdict

Siskiyou County has a mild, with an average annual temperature of 51.5°F, semi-arid conditions with only 22.8 inches of annual precipitation, occasional hot days — 47.93333333333333 per year above 90°F, light snow averaging 16.4 inches per year. This climate profile shapes everything from energy costs to outdoor recreation opportunities.

Seasonal Breakdown

Winters are cold, with January averaging 35.8°F. summers are warm — July averages 71.2°F. The 35°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 Siskiyou County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.

Regional Context

Siskiyou County is 7.2°F cooler than the California statewide average of 58.7°F, it is somewhat drier than average for California.

Climate Profile

About Siskiyou County Weather

California's Rugged Northern Frontier

Siskiyou averages 51.5°F, making it significantly cooler than the national median. This reflects its high-latitude position near the Oregon border.

Deep Below the State Temperature Average

The county is 7.2 degrees cooler than the California state average of 58.7°F. It represents the colder, more mountainous side of the Golden State's climate.

Drier and Colder Than Its Neighbors

Siskiyou receives 22.8 inches of rain, which is less than half the amount Shasta receives. However, it still records 16.4 inches of snow, identifying it as a true alpine environment.

Freezing Winters and Intense Heat Days

Winters are harsh for California, averaging just 36.5°F with significant snow. Paradoxically, the county also sees 48 days of extreme heat with a July average of 71.2°F.

Winter Wood Stoves and Summer Cooling

Heating systems must be robust to handle the 36.5°F winter average and 16.4 inches of snow. Prepare for a true four-season cycle that includes nearly 50 days of extreme heat.

Frequently Asked Questions

What is the average temperature in Siskiyou County?
The average annual temperature in Siskiyou County, CA is 51.5°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does Siskiyou County get?
Siskiyou County receives an average of 22.8 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 Siskiyou County?
Yes, Siskiyou County receives an average of 16.4 inches of snowfall per year according to NOAA climate normals.
How hot does Siskiyou County get in summer?
The average summer temperature (June-August) in Siskiyou County is 68.1°F. The county experiences an average of 48 days per year above 90°F.
How cold are winters in Siskiyou County?
The average winter temperature (December-February) in Siskiyou County is 36.5°F. January, typically the coldest month, averages 35.8°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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