When to plant in Manhattan, IL
USDA Zone 6aEverything below — frost dates, hardiness zone, and what to plant when in Manhattan, Illinois — is derived from the closest NOAA station with complete climate normals.
Zone 6a means Manhattan sees real winter cold, but a good range of perennials survive; the frost dates above govern when annual vegetables go out.
Frost probability
JOLIET BRANDON RD DAM · 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 Manhattan’s own odds, recorded at JOLIET BRANDON RD DAM.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 18 | May 1 | Apr 16 | Oct 2 | Oct 15 | Oct 27 |
| 32°F | May 7 | Apr 19 | Apr 3 | Oct 12 | Oct 25 | Nov 6 |
| 28°F | Apr 21 | Apr 5 | Mar 22 | Oct 23 | Nov 4 | Nov 21 |
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 Manhattan, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 25 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.
Manhattan planting FAQ
When is the last spring frost in Manhattan, IL?
On average, the last spring frost in Manhattan is around April 19 (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 Manhattan, IL?
The first fall frost in Manhattan typically arrives around October 25 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Manhattan in?
Manhattan is in USDA hardiness zone 6a. In zone 6a, winters are moderate — most common vegetables grow well in season.
How long is the growing season in Manhattan?
There are roughly 189 frost-free days in Manhattan (a moderate growing season), running from the average last frost around April 19 to the first fall frost near October 25.
When should I plant tomatoes in Manhattan?
In Manhattan, start tomato seeds indoors around February 22–March 8, then transplant seedlings outdoors around April 26 once the danger of frost has passed.
Never miss a window in Manhattan
An email when it’s time to start seeds, transplant, and sow — timed to Manhattan’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- New Lenox · 10 km
- Frankfort · 13 km
- Mokena · 15 km
- Joliet · 18 km
- Lockport · 19 km
- Crest Hill · 20 km
- Homer Glen · 21 km
- Richton Park · 21 km
Frost dates recorded at JOLIET BRANDON RD DAM, 14 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 Manhattan, IL — Frost Dates & Zone 6a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00114530. Retrieved from https://blissgarden.com/illinois/manhattan.