Frost dates 2026–2027

Frost dates for Hampshire, Illinois

Median (50% chance) dates of the last and first 32°F frost, from NOAA 1991–2020 climate normals at Marengo, 11 mi away (close match).

Last spring frostApr 28
First fall frostOct 12
166 frost-free days
Last spring frostApr 281 year in 10 after May 14
First fall frostOct 121 year in 10 by Sep 28
Growing season166 daysbetween median 32°F dates
Hardiness zoneZone 5b−15 to −10°F average extreme low

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Will it freeze in Hampshire 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 37°F. Above 36°F.

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

3 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 Hampshire

The median first fall hard-freeze date (28°F) is October 25, from NOAA’s 1991–2020 Climate Normals at Marengo. 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 26 · May 10 · May 26 Sep 21 · Oct 3 · Oct 16 145 days
32°F freeze Apr 15 · Apr 28 · May 14 Sep 28 · Oct 12 · Oct 27 166 days
28°F hard freeze Apr 3 · Apr 18 · May 4 Oct 7 · Oct 25 · Nov 6 188 days
NOAA NCEI U.S. Climate Normals 1991–2020, station USC00115326. How to read these probabilities.

Average high temperature by month

1991–2020 normals at Marengo

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 Hampshire, IL come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Marengo (station USC00115326, elevation 815 ft), 11 mi from Hampshire. 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 Hampshire

CityDistanceLast spring frostFirst fall frost
Pingree Grove, IL 4.3 mi Apr 26 Oct 18
Huntley, IL 5.0 mi Apr 25 Oct 22
Gilberts, IL 6.8 mi Apr 26 Oct 18
West Dundee, IL 8.7 mi Apr 26 Oct 18
Algonquin, IL 9.9 mi Apr 26 Oct 18
Genoa, IL 9.9 mi Apr 24 Oct 18
Marengo, IL 9.9 mi Apr 28 Oct 12
Lake in the Hills, IL 11 mi Apr 25 Oct 22
Elgin, IL 11 mi Apr 26 Oct 18
Carpentersville, IL 11 mi Apr 26 Oct 18

Frequently asked questions

When is the last frost in Hampshire?

On average, the last spring frost (32°F) in Hampshire is around April 28. In about 1 year in 10 it comes after May 14, and in 9 years in 10 it comes after April 15.

When is the first frost in Hampshire?

The first fall frost (32°F) usually arrives around October 12. There’s a 10% chance of a freeze by September 28 and a 90% chance by October 27.

Can it frost in Hampshire 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 10.

What growing zone is Hampshire?

Hampshire 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 60140. See growing zones in Illinois.

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