Idaho Historical Weather Data & Climate

Historical Climate Data for 10 Cities  •  1981–2025

°F / °C

Idaho Climate Overview

Idaho has an average annual temperature of 49.1°F (across all 10 cities) with approximately 481 mm of annual precipitation and average humidity of 61%. The warmest city is Caldwell with average July highs of 104.7°F, while Rexburg is the coldest with average January lows of -11.7°F. This page covers 45 years of NASA POWER climate data (1981–2025) including temperature, rainfall, humidity, wind speed, and solar radiation.

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Quick Climate Facts

(1981 – 2025)
Hottest City
🔥
Caldwell
Jul High: 104.7°F
Coldest City
❄️
Rexburg
Jan Low: -11.7°F
Wettest City
💧
Post Falls
758 mm/yr
Driest City
🏜️
Caldwell
341 mm/yr
Hottest Month
🌞
Jul
Avg High: 99.1°F
Coldest Month
🧊
Jan
Avg Low: 1.2°F
Cities With Data
🏙️
10
cities in Idaho
Data Coverage
📅
45 yrs
1981 – 2025

🏙️ Cities in Idaho — Weather History

📅 Idaho Monthly Climate Averages

🌡️ State-Wide Monthly Temperature

Average across all 10 cities · 1981–2025 · °F

🌧️ Monthly Precipitation

State-wide average · mm/month

📖 Idaho Seasonal Climate Guide

Jul is typically the warmest month across Idaho with average highs around 99.1°F, while Jan is the coldest with average lows near 1.2°F. Dec is the wettest month with approximately 62 mm of rainfall on average.
MonthMax TempMin TempAvg Temp Rain (mm)HumidityWind (m/s)Solar (kWh/m²)
Jan 43.5°F 1.2°F 22.3°F 56 86% 2.0 1.60
Feb 51.4°F 6.3°F 28.9°F 45 79% 2.2 2.60
Mar 64.2°F 17.1°F 40.6°F 50 70% 2.3 3.90
Apr 75.2°F 23.9°F 49.6°F 42 62% 2.3 5.30
May 84.4°F 29.7°F 57°F 50 57% 2.2 6.40
Jun 92.7°F 38.5°F 65.7°F 33 50% 2.1 7.20
Jul 99.1°F 48.6°F 73.9°F 16 39% 2.0 7.50
Aug 98.1°F 47.8°F 73°F 19 37% 1.9 6.40
Sep 91.6°F 36.3°F 64°F 24 42% 1.9 5.00
Oct 78.4°F 24.8°F 51.6°F 37 55% 2.0 3.30
Nov 61.2°F 14.4°F 37.8°F 54 72% 2.1 1.90
Dec 45.7°F 3°F 24.3°F 62 83% 2.1 1.30

📈 Idaho Yearly Climate Trends

🌡️ Annual Temperature Trend

State-wide avg annual high & low · Last 10 years

📈 Idaho Long-Term Climate Trends (1981–2025)

This chart shows how Idaho's average temperatures have shifted across 45 years. Use the range buttons to focus on recent decades or view the full historical record. Data is averaged across all 10 cities in the state.

🌧️ Annual Precipitation Trend

State-wide avg annual precipitation · Last 10 years · mm/year

🔗 Explore Cities in Idaho

Browse detailed weather history, monthly averages, and 45-year climate trends for every city in Idaho.

Looking for another state? 🇺🇸 Explore All US States & Cities →

❓ Frequently Asked Questions

What is the hottest city in Idaho?
Caldwell is the hottest city in Idaho with an average July high of 104.7°F based on 45 years of data. View Caldwell weather history →
What is the coldest city in Idaho?
Rexburg is the coldest city with average January lows of -11.7°F. View Rexburg weather history →
Which city in Idaho gets the most rain?
Post Falls is the wettest city in Idaho with approximately 758 mm of annual precipitation on average. View Post Falls weather history →
What is the warmest month in Idaho?
Jul is the warmest month across Idaho, with state-wide average highs of 99.1°F and average lows of 48.6°F.
How many cities in Idaho have weather data?
TownPillar has historical weather data for 10 cities in Idaho, covering 45 years of NASA POWER climate records from 1981 to 2025.
Which month has the most sunshine in Idaho?
Jul is the sunniest month across Idaho with an average solar radiation of 7.50 kWh/m²/day state-wide. This solar radiation data from NASA POWER is useful for solar energy planning, agriculture, and understanding seasonal sunshine availability.
Where does this climate data come from?
All data is sourced from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis data. It includes monthly temperature, precipitation, humidity, wind speed, and solar radiation at 0.5° × 0.625° spatial resolution.

📚 Data Source

All weather data is sourced from NASA POWER (Prediction of Worldwide Energy Resources). Data covers 45 years (1981–2025) across 10 cities in Idaho at monthly temporal resolution.