Frost dates 2026–2027

Frost dates for Wonder Lake, Illinois

Median (50% chance) dates of the last and first 32°F frost, from NOAA 1991–2020 climate normals at Mc Henry -Wg Stratton L&d, 6.6 mi away (close match).

Last spring frostMay 1
First fall frostOct 11
162 frost-free days
Last spring frostMay 11 year in 10 after May 19
First fall frostOct 111 year in 10 by Sep 27
Growing season162 daysbetween median 32°F dates
Hardiness zoneZone 5b−15 to −10°F average extreme low

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Will it freeze in Wonder Lake in the next 7 nights?

The earliest overnight low at or below 32°F in the available NWS frost forecast is Fri, Nov 6: 29°F (Fri, Nov 6, 6:00 PM CST to Sat, Nov 7, 6:00 AM CST).

Tonight: forecast low 36°F. Frost possible.

NWS forecast period: Thu, Nov 5, 6:00 PM CST to Fri, Nov 6, 6:00 AM CST.

4 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.

Overnight lows from the National Weather Service forecast for this location. This covers the available forecast window, not the first freeze of the whole season. Frost can form above 32°F on clear, calm nights.

Frost and freeze probabilities

Freeze dates shift from year to year. Spring percentages describe the chance of a freeze after the stated date; fall percentages describe the chance of a freeze by that date. The 10% spring date is the cautious one: a later freeze happens about 1 year in 10.

These dates describe historical probabilities, not this year’s forecast or the earliest and latest possible freezes. Different weather stations or probability thresholds can produce different published dates for the same city.

Average first hard freeze in Wonder Lake

The median first fall hard-freeze date (28°F) is October 22, from NOAA’s 1991–2020 Climate Normals at Mc Henry -Wg Stratton L&d. This is the 50% probability date, not a forecast for this year.

TemperatureLast spring date
90% · 50% · 10% chance of a later freeze
First fall date
10% · 50% · 90% chance of an earlier freeze
Season
36°F frost possible Apr 28 · May 12 · May 28 Sep 19 · Oct 1 · Oct 14 141 days
32°F freeze Apr 16 · May 1 · May 19 Sep 27 · Oct 11 · Oct 24 162 days
28°F hard freeze Apr 5 · Apr 19 · May 6 Oct 7 · Oct 22 · Nov 4 185 days
NOAA NCEI U.S. Climate Normals 1991–2020, station USC00115493. How to read these probabilities.

Average high temperature by month

1991–2020 normals at Mc Henry -Wg Stratton L&d

Average low temperature by month

Months with lows near or below freezing carry frost risk

Where these frost dates come from

The frost dates for Wonder Lake, IL come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Mc Henry -Wg Stratton L&d (station USC00115493, elevation 736 ft), 6.6 mi from Wonder Lake. Local conditions (valleys, hilltops, distance to water, city heat) can shift frost dates by days or weeks. The hardiness zone is from the 2023 USDA Plant Hardiness Zone Map (USDA ARS and Oregon State University PRISM). See our methodology.

Frost dates near Wonder Lake

CityDistanceLast spring frostFirst fall frost
McHenry, IL 3.7 mi May 1 Oct 11
Johnsburg, IL 5.0 mi May 1 Oct 11
Woodstock, IL 6.2 mi Apr 25 Oct 22
Spring Grove, IL 7.5 mi Apr 30 Oct 13
Lakemoor, IL 8.1 mi May 1 Oct 11
Fox Lake, IL 9.3 mi Apr 23 Oct 21
Crystal Lake, IL 9.9 mi Apr 25 Oct 22
Island Lake, IL 9.9 mi May 1 Oct 11
Volo, IL 9.9 mi May 1 Oct 11
Twin Lakes, WI 11 mi Apr 30 Oct 13

Frequently asked questions

When is the last frost in Wonder Lake?

On average, the last spring frost (32°F) in Wonder Lake is around May 1. In about 1 year in 10 it comes after May 19, and in 9 years in 10 it comes after April 16.

When is the first frost in Wonder Lake?

The first fall frost (32°F) usually arrives around October 11. There’s a 10% chance of a freeze by September 27 and a 90% chance by October 24.

Can it frost in Wonder Lake after the last frost date?

Yes. Frost can form on clear, calm nights even when the air stays above 32°F. Temperatures of 36°F or lower, cold enough for frost on exposed plants, have a 50% chance of occurring after May 12.

What growing zone is Wonder Lake?

Wonder Lake is in USDA Plant Hardiness Zone 5b (average annual extreme minimum temperature −15 to −10°F), based on the 2023 USDA map for ZIP code 60097. See growing zones in Illinois.

More: all Illinois frost dates · Illinois growing zones · frost vs. freeze