Photo: Myotus · CC BY 4.0Isle sits near the bottom of U.S. towns for winter warmth
Sunny July days climb to about 79°. By July afternoons alone, it runs cooler than 94% of U.S. towns. Decade by decade the climate has edged up, 1.9° above 1901–2000. Long walks are most pleasant from May to September, when afternoons reach 66–79°.
A year in Isle at a glance
Each month’s typical high and low, and what it brings.
What stands out about Isle’s climate
Compared with towns across the U.S., with Isle’s place in Minnesota beside it.
What a year in Isle feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 144 frost-free days a year
In half of years the last 32° night comes by May 10 and the first by October 3. Frost and day counts come from NOAA’s station at Isle 12n, MN, 13 miles from the town’s center, at about the same height.
The 2023 USDA map puts Isle’s center in zone 4a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −27°. 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 32 inches of snow a winter
Snow, measured at Onamia Rs, MN, falls mostly in January and March. Precipitation (rain plus melted snow) adds up to 31 inches a year; July is the wettest month and January the driest. Rain or snow falls on about 89 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Isle
96% of the work is heating, so the furnace matters far more than the air conditioner. Months averaging under 55° run from October through May.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Isle 12n, MN.
Living with Isle’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
144 frost-free days in zone 4a. The last frost comes by May 10 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 3.
Months with highs of 62–84° and lows of 40° or more: May, June, July, August and September. 0.1 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Isle from natural hazards, river flooding is the largest share (73%); heat waves, cold waves, winter storms and ice storms together are 12%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Isle and its neighbors
Every town next door is within a degree of Isle in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Isle’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 |
|---|---|---|---|---|
| Isle, MN | 2° | 79° | 31" | 32" |
| Antigo, WI | 5° | 79° | 32" | 54" |
| Watertown, SD | 2° | 81° | 25" | 41" |
| Estherville, IA | 7° | 82° | 31" | 38" |
| Kingsford, MI | 5° | 80° | 29" | 61" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Isle averaged 1.9° warmer than the 1900s. The biggest change is in December (+4.1°).
A bigger shift than in 83% 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 Isle compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Isle’s place among Minnesota’s.
Isle weather by month
Highs, lows and precipitation from NOAA’s grid at Isle’s center; snow, wet days and snow on the ground from Onamia Rs, MN. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | 30-yr range |
|---|---|---|---|---|---|---|
| January | 20° | 2° | 0.7" | 8.1" | 5 | −1° – 25° |
| February | 26° | 5° | 0.8" | 5.2" | 5 | 4° – 30° |
| March | 38° | 18° | 1.4" | 7.4" | 7 | 19° – 42° |
| April | 53° | 30° | 2.4" | 2.1" | 9 | 32° – 49° |
| May | 66° | 42° | 3.6" | 0.0" | 10 | 48° – 60° |
| June | 75° | 52° | 4.5" | 0.0" | 10 | 60° – 68° |
| July | 79° | 57° | 4.6" | 0.0" | 9 | 61° – 73° |
| August | 78° | 55° | 4.0" | 0.0" | 8 | 60° – 70° |
| September | 69° | 47° | 3.2" | 0.0" | 8 | 51° – 64° |
| October | 55° | 36° | 3.0" | 0.3" | 8 | 38° – 50° |
| November | 38° | 23° | 1.5" | 4.5" | 5 | 21° – 41° |
| December | 25° | 10° | 1.0" | 4.0" | 5 | 5° – 26° |
| Year | 52° | 31° | 30.7" | 31.6" | 89 |
How much a month can swing
A normal is an average. January swings the most: from 1991 to 2020 its average ranged from -1° to 25°. June is the most reliable, staying within 8°.
Where Isle’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 Isle’s center.
- Snow: Onamia Rs, MN.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Isle 12n, MN, 13 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 Isle’s climate
What is the weather like in Isle?
A typical July afternoon reaches 79°, a January night drops to 2°, and about 32 inches of snow falls in a normal winter. Colder January nights than all but 72 U.S. towns; cooler July afternoons than 94% of U.S. towns.
How cold does it get in Isle in winter?
January nights average 2°. About 176 nights a year reach 32° or below and 43 reach 0° or below. In the coldest January of the last 30 years the month averaged −1°.
How much snow does Isle get?
About 32 inches in a normal winter at Onamia Rs, MN, most of it in January and March.
How hot does it get in Isle?
July, with a typical high of 79° and a low of 57°. About 2 days a year reach 90° (Isle 12n, MN).
When is the first and last frost in Isle?
In half of years the last spring frost (32°) comes by May 10 and the first fall frost by October 3, about 144 frost-free days, at Isle 12n, MN.
What growing zone is Isle in?
Zone 4a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −27°.
What is the best time of year to visit Isle?
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 Isle getting warmer?
Yes: 1991–2020 averaged 1.9° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 83% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Isle.
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.