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Lewis and Clark County Climate

Lewis and Clark County, Montana

NOAA NCEI 1991-2020 Climate Normals
JanFebMarAprMayJunJulAugSepOctNovDec43.3°AVG °F

Avg Annual Temp

43.3°F

Annual Precip

15.6"

Annual Snowfall

32.6"

Extreme Heat Days

15

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Dry
Wet= snowfall
0.7"
0.9"
0.8"
1.5"
2.5"
2.8"
1.1"
1.2"
1.3"
1.2"
0.8"
0.8"
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Growing Season & Gardening

USDA Hardiness Zone

4b

Minimum winter temperature range for plant survival

Growing Degree Days

1,566

Favors cool-season crops

Last spring frost (32°F): 05/21
First fall frost (32°F): 09/21

Seasonal Overview

Comfort ZoneSpring34°50°4.8"Summer58°66°5.1"Fall32°55°3.4"Winter25°26°2.4"20°40°60°80°100°

National Comparison

Warmer than 8% of US counties
Wetter than 8% of US counties
More seasonal variation than 41% of US counties

7-Day Outlook

Forecast

Current Conditions

Air Quality

Safety

Weather Alerts

Climate Advisory: Lewis and Clark County

Climate Verdict

Lewis and Clark County has a cool, averaging 43.3°F annually, semi-arid conditions with only 15.6 inches of annual precipitation, rare extreme heat with only 14.928571428571429 days above 90°F annually, moderate snowfall of 32.6 inches annually. This climate profile shapes everything from energy costs to outdoor recreation opportunities.

Seasonal Breakdown

Winters are very cold — January averages 24.7°F. summers are pleasantly cool with July averaging 65.7°F. The 41°F seasonal variation provides noticeable but manageable change.

Outdoor & Gardening Guidance

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

Regional Context

Lewis and Clark County closely matches the Montana statewide average temperature of 43.7°F.

Climate Profile

About Lewis and Clark County Weather

A Cool Continental Climate in the Rockies

Lewis and Clark County maintains an annual average temperature of 43.3°F, significantly cooler than the national county median of roughly 54°F. This semi-arid region experiences dry air and sharp temperature shifts typical of high-elevation mountain environments.

Matching the Montana State Average

The county's average temperature sits just below the Montana state average of 43.7°F. With 15.6 inches of annual precipitation, it aligns closely with the state's typical moisture levels of 15.4 inches.

Warmer and Drier Than High-Altitude Neighbors

At 43.3°F, the county is notably warmer than neighboring Meagher County, which averages only 41.4°F. It also sees far less snow than nearby Missoula County, recording 32.6 inches compared to Missoula's 73.9 inches.

Moderate Summers Meet Sharp Winter Chills

July brings a pleasant average of 65.7°F, though residents face 15 extreme heat days over 90°F annually. Winters are brisk with a January average of 24.7°F and reliable, though not overwhelming, snowfall.

Preparing for Arid Extremes and Elevation

Homeowners should prioritize efficient heating systems for the 25.2°F winter average and consider moderate cooling for the two weeks of summer heat. Given the 15.6 inches of precipitation, water-wise landscaping is essential for local gardens.

Frequently Asked Questions

What is the average temperature in Lewis and Clark County?
The average annual temperature in Lewis and Clark County, MT is 43.3°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does Lewis and Clark County get?
Lewis and Clark County receives an average of 15.6 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 Lewis and Clark County?
Yes, Lewis and Clark County receives an average of 32.6 inches of snowfall per year according to NOAA climate normals.
How hot does Lewis and Clark County get in summer?
The average summer temperature (June-August) in Lewis and Clark County is 62.6°F. The county experiences an average of 15 days per year above 90°F.
How cold are winters in Lewis and Clark County?
The average winter temperature (December-February) in Lewis and Clark County is 25.2°F. January, typically the coldest month, averages 24.7°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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