weatherbycounty

O'Brien County Climate

JanFebMarAprMayJunJulAugSepOctNovDec46.1°AVG °F

Avg Annual Temp

46.1°F

Annual Precip

31.5"

Annual Snowfall

39.0"

Extreme Heat Days

11

days >= 90°F/yr

Monthly Temperature

54.4°F avgJFMAMJJASOND

Precipitation Calendar

Dry
Wet= snowfall
0.9"
1.0"
1.8"
3.3"
4.2"
4.8"
3.6"
3.4"
3.3"
2.4"
1.5"
1.1"
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Growing Season & Gardening

USDA Hardiness Zone

5a

Minimum winter temperature range for plant survival

Growing Degree Days

2,805

Supports most vegetables & fruits

Last spring frost (32°F): 05/01
First fall frost (32°F): 10/07

Seasonal Overview

Comfort ZoneSpring33°59°9.4"Summer69°73°11.9"Fall34°62°7.3"Winter16°21°3.0"20°40°60°80°100°

National Comparison

Warmer than 17% of US counties
Wetter than 28% of US counties
More seasonal variation than 94% of US counties

7-Day Outlook

Forecast

Current Conditions

Air Quality

Safety

Weather Alerts

Climate Advisory: O'Brien County

Climate Verdict

O'Brien County has a cool, averaging 46.1°F annually, moderate rainfall of 31.5 inches per year, rare extreme heat with only 11.300000000000002 days above 90°F annually, moderate snowfall of 39.0 inches annually. This climate profile shapes everything from energy costs to outdoor recreation opportunities.

Seasonal Breakdown

Winters are very cold — January averages 16.0°F. summers are warm — July averages 72.7°F. Residents experience a substantial 57°F difference between winter and summer.

Outdoor & Gardening Guidance

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

Regional Context

O'Brien County closely matches the Iowa statewide average temperature of 48.0°F, it is somewhat drier than average for Iowa.

Climate Profile

About O'Brien County Weather

Cold and Dry Northern Climate

O'Brien County's 46.1°F average is well below the national median. It receives a moderate 31.5 inches of precipitation annually, which is low for the state.

Below the State Average

This county is 1.9 degrees colder than the Iowa state average of 48.0°F. Its northern location leads to much harsher winters than southern Iowa.

Northern Snow Patterns

O'Brien is snowier than Monona but slightly warmer than Osceola. It experiences 39.0 inches of snow annually, which is significantly higher than counties further south.

Long Winters, Mild Summers

Winters are defined by 39 inches of snow and a 16.0°F January average. Summer is mild, with only 11 days per year reaching or exceeding 90°F.

Invest in Winter Tools

A high-quality snowblower is a necessity for the 39-inch annual snowfall. Energy bills will skew toward heating rather than cooling, given the rare occurrence of extreme heat.

Frequently Asked Questions

What is the average temperature in O'Brien County?
The average annual temperature in O'Brien County, IA is 46.1°F, based on NOAA 30-year climate normals (1991-2020).
How much rain does O'Brien County get?
O'Brien County receives an average of 31.5 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 O'Brien County?
Yes, O'Brien County receives an average of 39.0 inches of snowfall per year according to NOAA climate normals.
How hot does O'Brien County get in summer?
The average summer temperature (June-August) in O'Brien County is 70.7°F. The county experiences an average of 11 days per year above 90°F.
How cold are winters in O'Brien County?
The average winter temperature (December-February) in O'Brien County is 19.3°F. January, typically the coldest month, averages 16.0°F.

Track your own weather in O'Brien County

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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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