Photo: daBinsi · CC BY 2.0Winter nights in Corunna are colder than in 81% of U.S. towns
Peak summer warmth arrives in July, with afternoons near 82°. It is a dry place: less rain and snow fall here than on 79% of U.S. towns. The latest 30-year average runs 1.5° warmer than 1901–2000’s, with February up the most. The heating season runs November to April: each of those months averages under 50°.
A year in Corunna at a glance
Each month’s typical high and low, and what it brings.
What stands out about Corunna’s climate
Compared with towns across the U.S., with Corunna’s place in Michigan beside it.
What a year in Corunna feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 164 frost-free days a year
In half of years the last 32° night comes by May 1 and the first by October 15. Frost and day counts come from NOAA’s station at Owosso Wwtp, MI, 4 miles from the town’s center, at about the same height.
The 2023 USDA map puts Corunna’s center in zone 6a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −8°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 38 inches of snow a winter
Snow, measured at Owosso Wwtp, MI, falls mostly in January. Precipitation (rain plus melted snow) adds up to 34 inches a year; May is the wettest month and February the driest. Rain or snow falls on about 140 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Corunna
92% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through April.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Owosso Wwtp, MI.
Living with Corunna’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
164 frost-free days in zone 6a. The last frost comes by May 1 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 15.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August and September. 1.4 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Corunna from natural hazards, river flooding is the largest share (38%); heat waves, cold waves, winter storms and ice storms together are 21%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Corunna and similar climates
TownRatings has no climate map of the towns around Corunna yet.
Climates most like Corunna’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Corunna, MI | 16° | 82° | 34" | 38" |
| North Dansville, NY | 17° | 82° | 33" | 36" |
| Pleasant Prairie, WI | 16° | 82° | 35" | 36" |
| Zion, IL | 16° | 82° | 36" | 36" |
| Sayre, PA | 17° | 84° | 37" | 35" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in Corunna averaged 1.5° warmer than the 1900s. The biggest change is in February (+3.0°).
A bigger shift than in 56% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Corunna compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Corunna’s place among Michigan’s.
Corunna weather by month
Highs, lows and precipitation from NOAA’s grid at Corunna’s center; snow, wet days and snow on the ground from Owosso Wwtp, MI. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 30° | 16° | 2.1" | 12.4" | 13 | 23 | 13° – 33° |
| February | 33° | 17° | 1.8" | 8.9" | 10 | 19 | 11° – 34° |
| March | 44° | 25° | 2.0" | 4.0" | 10 | 9 | 25° – 49° |
| April | 57° | 35° | 3.4" | 0.8" | 13 | 1 | 40° – 52° |
| May | 69° | 47° | 3.9" | 0.0" | 14 | 0 | 50° – 64° |
| June | 79° | 56° | 3.6" | 0.0" | 12 | 0 | 64° – 72° |
| July | 82° | 60° | 3.4" | 0.0" | 10 | 0 | 66° – 76° |
| August | 80° | 59° | 3.3" | 0.0" | 12 | 0 | 64° – 74° |
| September | 74° | 51° | 2.8" | 0.0" | 11 | 0 | 56° – 67° |
| October | 60° | 40° | 3.1" | 0.2" | 13 | 0 | 46° – 57° |
| November | 47° | 31° | 2.5" | 2.1" | 11 | 2 | 32° – 46° |
| December | 35° | 23° | 1.9" | 9.9" | 12 | 14 | 17° – 40° |
| Year | 58° | 38° | 33.7" | 38.3" | 140 | 67 |
How much a month can swing
A normal is an average. March swings the most: from 1991 to 2020 its average ranged from 25° to 49°. June is the most reliable, staying within 9°.
Where Corunna’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Corunna’s center.
- Snow: Owosso Wwtp, MI.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Owosso Wwtp, MI, 4 miles from the town’s center, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Corunna’s climate
What is the weather like in Corunna?
A typical July afternoon reaches 82°, a January night drops to 16°, and about 38 inches of snow falls in a normal winter. Colder January nights than 81% of U.S. towns; cooler July afternoons than 77% of U.S. towns.
How cold does it get in Corunna in winter?
January nights average 16°. About 149 nights a year reach 32° or below and 9 reach 0° or below. In the coldest January of the last 30 years the month averaged 13°.
How much snow does Corunna get?
About 38 inches in a normal winter at Owosso Wwtp, MI, most of it in January, with snow on the ground about 67 days a year.
How hot does it get in Corunna?
July, with a typical high of 82° and a low of 60°. About 8 days a year reach 90° (Owosso Wwtp, MI).
When is the first and last frost in Corunna?
In half of years the last spring frost (32°) comes by May 1 and the first fall frost by October 15, about 164 frost-free days, at Owosso Wwtp, MI.
What growing zone is Corunna in?
Zone 6a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −8°.
What is the best time of year to visit Corunna?
By one simple rule (highs of 62–84° and lows of 40° or more), May, June, July, August and September. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Corunna getting warmer?
Yes: 1991–2020 averaged 1.5° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 56% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Corunna.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.