Illinois Traction System Mackinaw Depot · Photo: Ammodramus · CC0Midwinter lows in Mackinaw sink below those of 76% of U.S. towns
Peak summer warmth arrives in July, with afternoons near 86°. Winter and summer sit 69° apart. Its yearly precipitation falls short of 67% of U.S. towns. Tender plants can go out after about April 21; in half of years the first frost comes by October 17.
A year in Mackinaw at a glance
Each month’s typical high and low, and what it brings.
What stands out about Mackinaw’s climate
Compared with towns across the U.S., with Mackinaw’s place in Illinois beside it.
What a year in Mackinaw feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 178 frost-free days a year
In half of years the last 32° night comes by April 21 and the first by October 17. Frost and day counts come from NOAA’s station at Congerville 2nw, IL, 9 miles from the town’s center, at about the same height.
The 2023 USDA map puts Mackinaw’s center in zone 6a: the coldest night of a typical winter, averaged over 1991–2020, reaches about −10°. 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 24 inches of snow a winter
Snow, measured at Mackinaw 3wsw, IL, is heaviest from January through February, about 7 inches a month. Precipitation (rain plus melted snow) adds up to 38 inches a year; May is the wettest month and February the driest. Rain or snow falls on about 103 days a year.
Rain + melted snow by month
Inches of water
Snowfall by month
Inches of snow
Heating and cooling a home in Mackinaw
84% of the work is heating. 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 Congerville 2nw, IL.
Living with Mackinaw’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
178 frost-free days in zone 6a. The last frost comes by Apr 21 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 17.
Months with highs of 62–84° and lows of 40° or more: April, May, June, August, September and October. 0.0 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Mackinaw from natural hazards, river flooding is the largest share (46%); heat waves, cold waves, winter storms and ice storms together are 26%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Mackinaw and similar climates
TownRatings has no climate map of the towns around Mackinaw yet.
Climates most like Mackinaw’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 |
|---|---|---|---|---|
| Mackinaw, IL | 17° | 86° | 38" | 24" |
| Centerville, IA | 15° | 85° | 38" | 22" |
| Defiance, OH | 19° | 85° | 37" | 24" |
| Savannah, MO | 18° | 87° | 37" | 21" |
| Lock Haven, PA | 19° | 86° | 41" | 30" |
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 Mackinaw averaged 1.4° warmer than the 1900s. The biggest change is in December (+2.7°).
A bigger shift than in 55% 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 Mackinaw compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Mackinaw’s place among Illinois’.
Mackinaw weather by month
Highs, lows and precipitation from NOAA’s grid at Mackinaw’s center; snow, wet days and snow on the ground from Mackinaw 3wsw, IL. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 34° | 17° | 2.1" | 7.2" | 8 | 14 | 18° – 37° |
| February | 39° | 21° | 1.9" | 7.0" | 7 | 9 | 17° – 41° |
| March | 51° | 30° | 2.5" | 3.0" | 9 | 3 | 33° – 55° |
| April | 64° | 40° | 3.9" | 0.4" | 11 | 0 | 44° – 58° |
| May | 74° | 52° | 4.6" | 0.0" | 11 | 0 | 57° – 72° |
| June | 83° | 61° | 4.1" | 0.0" | 10 | 0 | 67° – 75° |
| July | 86° | 64° | 4.2" | 0.0" | 8 | 0 | 70° – 81° |
| August | 84° | 62° | 3.6" | 0.0" | 8 | 0 | 67° – 78° |
| September | 79° | 54° | 3.2" | 0.0" | 7 | 0 | 61° – 71° |
| October | 66° | 42° | 3.2" | 0.0" | 9 | 0 | 49° – 60° |
| November | 51° | 32° | 2.8" | 1.2" | 8 | 1 | 34° – 50° |
| December | 38° | 22° | 2.2" | 5.6" | 8 | 7 | 16° – 41° |
| Year | 62° | 41° | 38.2" | 24.4" | 103 | 33 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 17° to 41°. June is the most reliable, staying within 8°.
Where Mackinaw’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 Mackinaw’s center.
- Snow: Mackinaw 3wsw, IL.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Congerville 2nw, IL, 9 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 Mackinaw’s climate
What is the weather like in Mackinaw?
A typical July afternoon reaches 86°, a January night drops to 17°, and about 24 inches of snow falls in a normal winter. Colder January nights than 76% of U.S. towns; hotter July afternoons than 52% of U.S. towns.
How cold does it get in Mackinaw in winter?
January nights average 17°. About 134 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 18°.
How much snow does Mackinaw get?
About 24 inches in a normal winter at Mackinaw 3wsw, IL, heaviest from January through February, about 7 inches a month, with snow on the ground about 33 days a year.
How hot does it get in Mackinaw?
July, with a typical high of 86° and a low of 64°. About 24 days a year reach 90° (Congerville 2nw, IL).
When is the first and last frost in Mackinaw?
In half of years the last spring frost (32°) comes by April 21 and the first fall frost by October 17, about 178 frost-free days, at Congerville 2nw, IL.
What growing zone is Mackinaw in?
Zone 6a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about −10°.
What is the best time of year to visit Mackinaw?
By one simple rule (highs of 62–84° and lows of 40° or more), April, May, June, August, September and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Mackinaw getting warmer?
Yes: 1991–2020 averaged 1.4° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 55% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Mackinaw.
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.