Hamilton has cold, snowy winters and warm summers
A typical July afternoon reaches 85°, a January night drops to 14°, and about 30 inches of snow falls in a normal winter.
A year in Hamilton at a glance
Each month’s typical high and low, and what it brings.
What stands out about Hamilton’s climate
Read from where Hamilton sits among Iowa’s towns. The page puts what stands out first.
Warmer than it used to be
The last 30 years in Hamilton averaged 0.4° warmer than the 1900s. The biggest change is in December (+2.0°).
A smaller shift than in 98% of U.S. towns.
Change by month
What a year in Hamilton feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 173 frost-free days a year
In half of years the last 32° night comes by April 24 and the first by October 16.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
Living with Hamilton’s climate
What the numbers mean for a garden, a driveway, a furnace and a free afternoon.
173 frost-free days. The last frost comes by Apr 24 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Oct 16.
About 30" a winter over 9 days with an inch or more, most in February. Snow covers the ground about 44 days a year.
Months averaging under 55° run from October through April. Heating is 88% of the year’s heating-and-cooling load.
About 15 days a year reach 90°, and July afternoons average 85°.
The nicest months are May, June, August, September and October.
Parks & trails →Normals are averages. Ice storms, nor’easters, floods and heat waves are on the natural hazards page.
Natural hazards →30 inches of snow, 36 of rain and melt
June is the wettest month and January the driest. Rain or snow falls on about 105 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
How Hamilton compares
Against every U.S. town on TownTapestry, each counted once, with its place in Iowa.
Hamilton weather by month
Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 31° | 14° | 1.1" | 7.4" | 7 | 16 | 15° – 35° |
| February | 36° | 18° | 1.4" | 8.4" | 7 | 12 | 16° – 38° |
| March | 49° | 29° | 2.0" | 3.9" | 8 | 4 | 31° – 54° |
| April | 62° | 40° | 3.8" | 1.1" | 11 | 0 | 43° – 58° |
| May | 72° | 51° | 4.8" | 0 | 12 | 0 | 56° – 69° |
| June | 81° | 61° | 5.2" | 0 | 12 | 0 | 68° – 75° |
| July | 85° | 65° | 4.2" | 0 | 9 | 0 | 69° – 82° |
| August | 83° | 62° | 4.2" | 0 | 9 | 0 | 67° – 78° |
| September | 77° | 54° | 3.5" | 0 | 8 | 0 | 59° – 70° |
| October | 64° | 42° | 2.8" | 0.4" | 8 | 0 | 47° – 58° |
| November | 49° | 30° | 2.0" | 1.9" | 7 | 2 | 31° – 50° |
| December | 37° | 20° | 1.4" | 6.9" | 7 | 8 | 12° – 37° |
| Year | 61° | 40° | 36.4" | 30.0" | 105 | 44 |
Heating and cooling a home in Hamilton
88% of the work is heating, so the furnace matters far more than the air conditioner.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. Source: NOAA station normals.
How much a month can swing
A normal is an average. December swings the most: from 1991 to 2020 its average ranged from 12° to 37°. June is the most reliable, staying within 6°.
Common questions about Hamilton’s climate
What is the coldest month in Hamilton?
January, with a typical high of 31° and a low of 14°.
What is the hottest month in Hamilton?
July, with a typical high of 85° and a low of 65°. About 15 days a year reach 90°.
How much snow does Hamilton get?
About 30 inches in a normal winter, most of it in February.
When is the first frost in Hamilton?
In half of years the first 32° night comes by October 16, and the last spring frost by April 24.
What is the rainiest month in Hamilton?
June, with 5.2 inches of rain and melted snow. The year totals 36 inches.
Neighbors talk weather
Gardens, snow, and the best days of the year in Hamilton.
Your answer becomes a post in Town Square.
Temperatures and rainfall come from NOAA’s gridded climate normals for Hamilton itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Albia 3 Nne, IA (10 mi) away. Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000. Today’s forecast: National Weather Service.