When to plant in Lisle, IL
USDA Zone 5bEverything below — frost dates, hardiness zone, and what to plant when in Lisle, Illinois — is derived from the closest NOAA station with complete climate normals.
In zone 5b, Lisle gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
Frost probability
LISLE-MORTON ARBORETUM · 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 Lisle’s own odds, recorded at LISLE-MORTON ARBORETUM.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 25 | May 9 | Apr 25 | Sep 22 | Oct 6 | Oct 18 |
| 32°F | May 14 | Apr 28 | Apr 14 | Oct 1 | Oct 16 | Oct 29 |
| 28°F | May 4 | Apr 16 | Apr 2 | Oct 12 | Oct 26 | Nov 8 |
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 Lisle, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 18 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.
Lisle planting FAQ
When is the last spring frost in Lisle, IL?
On average, the last spring frost in Lisle is around April 28 (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 Lisle, IL?
The first fall frost in Lisle typically arrives around October 16 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Lisle in?
Lisle 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 Lisle?
Lisle has about 171 frost-free days — a moderate growing season — between the average last spring frost (April 28) and first fall frost (October 16).
When should I plant tomatoes in Lisle?
For Lisle, sow tomatoes indoors about March 3–March 17 and move the seedlings out around May 5, after the last spring frost.
Never miss a window in Lisle
An email when it’s time to start seeds, transplant, and sow — timed to Lisle’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Downers Grove · 6 km
- Woodridge · 7 km
- Wheaton · 7 km
- Naperville · 8 km
- Glen Ellyn · 9 km
- Warrenville · 9 km
- Westmont · 10 km
- Darien · 10 km
Frost dates recorded at LISLE-MORTON ARBORETUM, 3 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 Lisle, IL — Frost Dates & Zone 5b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00115097. Retrieved from https://blissgarden.com/illinois/lisle.