Gilliam County Climate

Gilliam County, Oregon

JanFebMarAprMayJunJulAugSepOctNovDec51.7°AVG °F

Avg Annual Temp

51.7°F

Annual Precip

11.7"

Annual Snowfall

15.4"

Extreme Heat Days

31.1

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Dry
Wet= snowfall
1.6"
1.1"
1.0"
1.0"
1.2"
0.8"
0.2"
0.3"
0.4"
1.0"
1.3"
1.7"
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Seasonal Overview

Comfort ZoneSpring43°58°3.2"Summer64°72°1.3"Fall41°64°2.7"Winter34°37°4.5"20°40°60°80°100°

National Comparison

Warmer than 38% of US counties
Wetter than 3% of US counties
More seasonal variation than 24% of US counties

Climate Profile

About Gilliam County Weather

A Warm and Very Arid Landscape

Gilliam County averages 51.7°F annually, placing it near the national median for temperature. Its 11.7 inches of annual precipitation, however, makes it one of the drier regions in the country.

Warmer but Much Drier than Oregon

The county is slightly warmer than the state average of 50.5°F. Conversely, it receives only a fraction of the state's average rainfall, seeing just 11.7 inches compared to 37.4 inches statewide.

A Warmer Pocket in Northern Oregon

Gilliam's average temperature of 51.7°F is higher than neighboring Jefferson County at 48.5°F. It shares a similar arid profile with other regional neighbors, maintaining very low annual precipitation.

Hot Summers and Light Snowfall

July is hot with an average of 72.3°F and 31 days of extreme heat exceeding 90°F. Winters are manageable, featuring a January average of 34.1°F and 15.4 inches of total annual snowfall.

Prioritize Cooling and Water Management

With 31 extreme heat days, efficient air conditioning is a necessity for residents. The extremely low rainfall of 11.7 inches suggests that xeriscaping is the most practical choice for outdoor spaces.

Frequently Asked Questions

What is the average temperature in Gilliam County?
The average annual temperature in Gilliam County, OR is 51.7°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does Gilliam County get?
Gilliam County receives an average of 11.7 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 Gilliam County?
Yes, Gilliam County receives an average of 15.4 inches of snowfall per year according to NOAA climate normals.
How hot does Gilliam County get in summer?
The average summer temperature (June-August) in Gilliam County is 69.4°F. The county experiences an average of 31.1 days per year above 90°F.
How cold are winters in Gilliam County?
The average winter temperature (December-February) in Gilliam County is 35.0°F. January, typically the coldest month, averages 34.1°F.

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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.

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