Last frost date in McHenry, IL

Average last frost
May 1

In McHenry, the last spring frost comes around May 1 in an average year. Wait until May 19 if you want 90% odds of no more frost. The first fall frost usually arrives about October 11, which leaves 162 frost-free days. An early freeze before September 27 happens one year in ten.

Safe after (10% risk)
May 19
Average first frost
Oct 11
Frost-free season
162 days
Hard freeze (28°F) ends
Apr 19
Next 7 nights in McHenry

No frost in the next 7 nights

Later than usual: the average first frost here is October 11.

National Weather Service forecast, updated Oct 22, 12:57 UTC

  1. ThuOct 2246°
  2. FriOct 2347°
  3. SatOct 2450°
  4. SunOct 2550°
  5. MonOct 2647°
  6. TueOct 2743°
  7. WedOct 2844°
JanFebMarAprMayJunJulAugSepOctNovDecLast frost May 1First frost Oct 11162 frost-free daysBlue: chance of 32°F frost. Green: average frost-free season.JFMAMJJASOND162 frost-free days
Frost risk through the year at Mc Henry -wg Stratton L&d, 2.7 miles from McHenry.

Planting calendar for McHenry

Windows count forward or back from the average frost dates above. Click a crop for dates across Illinois.

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost
Warm-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
TomatoesMay 8–May 22
PumpkinsMay 15–May 29
SunflowersMay 1–May 22
CucumbersMay 15–May 22
CornMay 8–May 22
Sweet potatoesMay 22–Jun 5
WatermelonMay 15–May 29
Green beansMay 8–May 29
ZucchiniMay 8–May 22
OkraMay 22–Jun 5
PeppersMay 15–May 29
BasilMay 8–May 22
Butternut squashMay 8–May 22
CantaloupeMay 15–May 29
EggplantMay 15–May 29
Cool-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
PotatoesApr 3–Apr 17
OnionsMar 20–Apr 10
CarrotsApr 10–May 15
LettuceApr 17–May 8
BroccoliApr 3–Apr 17
BeetsApr 3–May 15
PeasMar 20–Apr 3
CabbageApr 3–Apr 17
RadishesMar 27–May 8
Brussels sproutsApr 17–May 1
SpinachMar 20–Apr 10
CilantroApr 17–May 8
KaleApr 3–Apr 17
Collard greensApr 3–Apr 17
TurnipsApr 3–Apr 17
DillMay 1–May 15
CeleryMay 8–May 15
CauliflowerApr 17–May 1
LeeksApr 17–May 1
Swiss chardApr 17–May 15
ParsleyApr 17–May 8
Fall bulbs and garlic
JanFebMarAprMayJunJulAugSepOctNovDec
Tulip bulbsSep 27–Nov 1
GarlicSep 20–Oct 25
Daffodil bulbsSep 13–Oct 25
Perennials
JanFebMarAprMayJunJulAugSepOctNovDec
StrawberriesApr 3–Apr 17
AsparagusApr 3–Apr 17

Frost probabilities

ThresholdSpring, 90% chance laterSpring, 50%Spring, 10%Fall, 10% chance earlierFall, 50%Fall, 90%
Light frost, 32°FApr 16May 1May 19Sep 27Oct 11Oct 24
Hard freeze, 28°FApr 5Apr 19May 6Oct 7Oct 22Nov 4

Read the spring 10% column as the date after which only one year in ten still gets frost. That is the safer date for tomatoes, peppers and basil.

Where these numbers come from

NOAA station Mc Henry -wg Stratton L&d (USC00115493) sits 2.7 miles from the center of McHenry at 736 feet. Its averages cover 1991 to 2020. Low spots, valleys and open fields can keep getting frost a week or two after the station stops; city centers and lakeshores usually get less of it.

Questions

When is the last frost in McHenry, IL?

The average last frost date in McHenry is May 1, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after May 19.

When is the first frost in McHenry?

The first frost in fall usually comes around October 11. One year in ten it arrives before September 27.

How long is the growing season in McHenry?

About 162 days between the average last and first frost.

When should I plant tomatoes in McHenry?

Plant tomato seedlings outside from May 8 to May 22. Start seeds indoors six to eight weeks earlier.

Nearby in Illinois

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