When to plant in Winnetka, IL
USDA Zone 6aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Winnetka, Illinois — all computed from Winnetka's nearest NOAA weather station.
In zone 6a, Winnetka gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
Frost probability
CHICAGO BOTANIC GARDEN · 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 Winnetka’s own odds, recorded at CHICAGO BOTANIC GARDEN.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 26 | May 8 | Apr 24 | Sep 28 | Oct 10 | Oct 24 |
| 32°F | May 11 | Apr 26 | Apr 11 | Oct 5 | Oct 21 | Nov 2 |
| 28°F | Apr 28 | Apr 13 | Mar 31 | Oct 17 | Nov 1 | Nov 14 |
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 Winnetka, 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.
Winnetka planting FAQ
When is the last spring frost in Winnetka, IL?
On average, the last spring frost in Winnetka is around April 26 (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 Winnetka, IL?
Expect Winnetka's first fall frost near October 21 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Winnetka in?
Winnetka 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 Winnetka?
Winnetka has about 178 frost-free days — a moderate growing season — between the average last spring frost (April 26) and first fall frost (October 21).
When should I plant tomatoes in Winnetka?
For Winnetka, sow tomatoes indoors about March 1–March 15 and move the seedlings out around May 3, after the last spring frost.
Never miss a window in Winnetka
An email when it’s time to start seeds, transplant, and sow — timed to Winnetka’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Wilmette · 3 km
- Glenview · 7 km
- Evanston · 8 km
- Skokie · 8 km
- Northbrook · 8 km
- Morton Grove · 8 km
- Highland Park · 10 km
- Niles · 10 km
Frost dates recorded at CHICAGO BOTANIC GARDEN, 5 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 Winnetka, IL — Frost Dates & Zone 6a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00111497. Retrieved from https://blissgarden.com/illinois/winnetka.