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Trinity County Climate

Trinity County, California

NOAA NCEI 1991-2020 Climate Normals
JanFebMarAprMayJunJulAugSepOctNovDec56.0°AVG °F

Avg Annual Temp

56.0°F

Annual Precip

35.3"

Annual Snowfall

5.9"

Extreme Heat Days

84

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Dry
Wet= snowfall
6.3"
5.3"
4.6"
2.6"
1.7"
0.8"
0.2"
0.2"
0.4"
2.0"
4.0"
7.1"
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Growing Season & Gardening

USDA Hardiness Zone

8b

Minimum winter temperature range for plant survival

Growing Degree Days

3,285

Supports most vegetables & fruits

Last spring frost (32°F): 04/23
First fall frost (32°F): 10/22

Seasonal Overview

Comfort ZoneSpring48°60°8.9"Summer67°74°1.2"Fall47°67°6.4"Winter40°44°18.7"20°40°60°80°100°

National Comparison

Warmer than 56% of US counties
Wetter than 35% of US counties
More seasonal variation than 11% of US counties

7-Day Outlook

Forecast

Current Conditions

Air Quality

Safety

Weather Alerts

Climate Advisory: Trinity County

Climate Verdict

Trinity County has a mild, with an average annual temperature of 56.0°F, moderate rainfall of 35.3 inches per year, significant summer heat with 84.26666666666667 days annually above 90°F, light snow averaging 5.9 inches per year. This climate profile shapes everything from energy costs to outdoor recreation opportunities.

Seasonal Breakdown

Winters are mild, with January temperatures averaging 41.2°F. summers are warm — July averages 74.4°F. The 33°F seasonal variation provides noticeable but manageable change. December is typically the coldest month and July the warmest.

Outdoor & Gardening Guidance

Summer outdoor activities should be planned for early morning or evening to avoid extreme heat.

Regional Context

Trinity County closely matches the California statewide average temperature of 58.7°F, it is also noticeably wetter, receiving 9.5 inches more precipitation than the state average, the county experiences 25.59574170373279 more extreme heat days than the state average.

Climate Profile

About Trinity County Weather

Above average national warmth

Trinity County’s 56.0°F average annual temperature is slightly higher than the national median. Despite its mountainous reputation, the county maintains a warmer profile than many northern U.S. regions. It bridges the gap between mountain cool and valley heat.

Cooler than the California norm

The county’s 56.0°F average is nearly three degrees cooler than the state average of 58.7°F. Its rugged terrain and elevation keep it from reaching the high averages of the coastal or desert counties. This makes it a cool-climate outlier in the Golden State.

High heat in the mountains

Surprisingly, Trinity sees 84 extreme heat days per year, nearly as many as the Central Valley. It receives 35.3 inches of annual rain, far more than the state average of 25.8 inches. This mix of high heat and high rain creates a unique ecological pocket.

Snowy winters and scorching summers

Trinity experiences 5.9 inches of annual snowfall and a winter average of 41.8°F. However, summer heat is intense, with an average of 71.5°F and frequent spikes over 90°F. The seasons are characterized by high contrast and dramatic shifts.

Invest in dual-season preparation

Residents need both reliable heating for snowy 41°F winters and powerful AC for 84 days of extreme heat. All-weather vehicle gear is recommended for the nearly six inches of snow. Yard maintenance should account for the heavy 35.3 inches of annual rainfall.

Frequently Asked Questions

What is the average temperature in Trinity County?
The average annual temperature in Trinity County, CA is 56.0°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does Trinity County get?
Trinity County receives an average of 35.3 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 Trinity County?
Yes, Trinity County receives an average of 5.9 inches of snowfall per year according to NOAA climate normals.
How hot does Trinity County get in summer?
The average summer temperature (June-August) in Trinity County is 71.5°F. The county experiences an average of 84 days per year above 90°F.
How cold are winters in Trinity County?
The average winter temperature (December-February) in Trinity County is 41.8°F. January, typically the coldest month, averages 41.2°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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