When to plant in McHenry, IL
USDA Zone 5bHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for McHenry, Illinois — all computed from McHenry's nearest NOAA weather station.
In zone 5b, McHenry gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
Frost probability
MC HENRY -WG STRATTON L&D · 1991–2020The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are McHenry’s own odds, recorded at MC HENRY -WG STRATTON L&D.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 28 | May 12 | Apr 28 | Sep 19 | Oct 1 | Oct 14 |
| 32°F | May 19 | May 1 | Apr 16 | Sep 27 | Oct 11 | Oct 24 |
| 28°F | May 6 | Apr 19 | Apr 5 | Oct 7 | Oct 22 | Nov 4 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Full-year planting calendar
Each bar is the exact window to take a planting action in McHenry, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 20 km · complete 32°F normalsWhen stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.
McHenry planting FAQ
When is the last spring frost in McHenry, IL?
On average, the last spring frost in McHenry is around May 1 (50% probability at 32°F, from 1991–2020 NOAA normals). Wait until after this date to set out tender plants like tomatoes and peppers.
When is the first fall frost in McHenry, IL?
In McHenry, the first 32°F freeze of fall lands around October 11 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is McHenry in?
McHenry is in USDA hardiness zone 5b. In zone 5b, winters are cold — pick cold-hardy varieties and protect tender crops.
How long is the growing season in McHenry?
McHenry has about 163 frost-free days — a moderate growing season — between the average last spring frost (May 1) and first fall frost (October 11).
When should I plant tomatoes in McHenry?
For McHenry, sow tomatoes indoors about March 6–March 20 and move the seedlings out around May 8, after the last spring frost.
Never miss a window in McHenry
An email when it’s time to start seeds, transplant, and sow — timed to McHenry’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Crystal Lake · 12 km
- Woodstock · 12 km
- Fox Lake · 14 km
- Cary · 14 km
- Wauconda · 14 km
- Round Lake · 16 km
- Lake in the Hills · 18 km
- Round Lake Beach · 18 km
Frost dates recorded at MC HENRY -WG STRATTON L&D, 4 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.
BlissGarden. "When to Plant in McHenry, IL — Frost Dates & Zone 5b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00115493. Retrieved from https://blissgarden.com/illinois/mchenry.