Des Plaines, Illinois, United States

Frost dates for Des Plaines

The full distribution rather than a single date. Every figure below is a percentile of 30 years of daily minimum temperatures at this location, expressed as the date it fell on.

Median last spring frost

26 April

Half of years are later than this. Not a planting date.

Median first autumn frost

22 October

The far end of the outdoor season.

Frost-free season

179 days

Between those two dates in a median year.

Last and first frost by severity

Read a row as: in this fraction of years, the last frost of spring had already happened by this date. The 90% column is the cautious planting date; the 10% column is the gamble.

Light frost — nights at or below 0°C (32°F). Air temperature reaches freezing. Kills basil, beans and unhardened tomatoes; hardy crops shrug it off.
Frost 1 year in 10 Median 9 years in 10 Earliest Latest
Last of spring 16 Apr 26 Apr 12 May 7 Apr 21 May
First of autumn 8 Oct 22 Oct 2 Nov 2 Oct 21 Nov
Frost-free days 200 179 149 every year on record saw this
Moderate frost — nights at or below -2.2°C (28°F). Damages half-hardy plants and most blossom. This is the threshold that decides a fruit crop.
Frost 1 year in 10 Median 9 years in 10 Earliest Latest
Last of spring 1 Apr 13 Apr 24 Apr 23 Mar 10 May
First of autumn 15 Oct 31 Oct 15 Nov 10 Oct 22 Nov
Frost-free days 228 201 174 every year on record saw this
Hard frost — nights at or below -4.4°C (24.1°F). Ground freezes and even hardy crops check their growth. Effectively the end of the outdoor year.
Frost 1 year in 10 Median 9 years in 10 Earliest Latest
Last of spring 16 Mar 29 Mar 11 Apr 26 Feb 17 Apr
First of autumn 1 Nov 13 Nov 26 Nov 21 Oct 9 Dec
Frost-free days 255 229 204 every year on record saw this

Dates in the southern hemisphere are computed on a growing year that starts in July, which is why "last of spring" falls where it should rather than in the middle of the calendar.

Chance of frost, week by week

Jan Mar Apr Jul Sep Oct Dec
Chance of at least one air frost during each week of the year, measured across the full record. The flat stretch in the middle is your frost-free season.

Temperature through the year

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Mean monthly temperature across the record. Months shown in blue average at least one air frost.

Monthly means and average number of frost nights.
Month Mean low Mean high Frost nights
January -9.8°C -1.5°C 29.4
February -8.2°C 1.1°C 26.6
March -2.4°C 7.7°C 23.1
April 2.6°C 14.5°C 8.7
May 8.8°C 20.7°C 0.3
June 14.7°C 26.3°C 0
July 17.6°C 28.7°C 0
August 17.2°C 28.3°C 0
September 12.9°C 24.7°C 0
October 5.9°C 17°C 3.2
November -0.7°C 8.4°C 18
December -6.3°C 1.4°C 27.5

Turn these dates into a planting calendar →

Nearby

Compare with places close by

Mount Prospect Zone 5b 6 km Last frost 26 Apr First 22 Oct Arlington Heights Zone 5b 10 km Last frost 26 Apr First 22 Oct Skokie Zone 7a 12 km Last frost 4 Apr First 17 Nov Palatine Zone 5b 15 km Last frost 26 Apr First 22 Oct Evanston Zone 7a 16 km Last frost 4 Apr First 17 Nov Hoffman Estates Zone 5b 16 km Last frost 26 Apr First 22 Oct Schaumburg Zone 5b 17 km Last frost 26 Apr First 22 Oct Oak Park Zone 7a 18 km Last frost 4 Apr First 17 Nov

Seasonal context

Rainfall and the growing season in Des Plaines

May has the highest average precipitation (121 mm); January has the lowest (44 mm). Compare this pattern with the planting windows and your water supply.

Jan 44 mm
Feb 51 mm
Mar 63 mm
Apr 94 mm
May 121 mm
Jun 112 mm
Jul 100 mm
Aug 105 mm
Sep 87 mm
Oct 91 mm
Nov 58 mm
Dec 58 mm

During wetter months, check that beds and containers drain after heavy rain. During drier months, plan how you will keep seeds and new transplants watered. Monthly averages can hide long dry spells and intense storms; they do not show soil moisture, humidity or this week's weather.

Source: NASA POWER, corrected MERRA-2 precipitation, 2001–2020. Values are approximate monthly totals, including the water equivalent of snow, from the nearest 0.5° × 0.625° grid cell. This reference period differs from the temperature record. Rainfall provides context and does not change the calculated planting dates. Method and limitations.

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