When to plant in Zion, IL
USDA Zone 6aEverything below — frost dates, hardiness zone, and what to plant when in Zion, Illinois — is derived from the closest NOAA station with complete climate normals.
In zone 6a, Zion gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
Frost probability
CHICAGO WAUKEGAN RGNL AP · 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 Zion’s own odds, recorded at CHICAGO WAUKEGAN RGNL AP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 27 | May 12 | Apr 28 | Sep 25 | Oct 10 | Oct 22 |
| 32°F | May 16 | Apr 30 | Apr 14 | Oct 5 | Oct 21 | Nov 2 |
| 28°F | May 2 | Apr 16 | Apr 2 | Oct 15 | 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 Zion, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 13 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.
Zion planting FAQ
When is the last spring frost in Zion, IL?
Zion's average last spring frost falls near April 30 — the 50% mark at 32°F in the 1991–2020 normals. Hold tender transplants until the risk has passed, then plant out.
When is the first fall frost in Zion, IL?
Expect Zion'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 Zion in?
Zion 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 Zion?
Zion has about 174 frost-free days — a moderate growing season — between the average last spring frost (April 30) and first fall frost (October 21).
When should I plant tomatoes in Zion?
For Zion, sow tomatoes indoors about March 5–March 19 and move the seedlings out around May 7, after the last spring frost.
Never miss a window in Zion
An email when it’s time to start seeds, transplant, and sow — timed to Zion’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Beach Park · 3 km
- Pleasant Prairie · 8 km
- Waukegan · 10 km
- Gurnee · 12 km
- Kenosha · 14 km
- Lindenhurst · 15 km
- North Chicago · 16 km
- Gages Lake · 16 km
Frost dates recorded at CHICAGO WAUKEGAN RGNL AP, 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 Zion, IL — Frost Dates & Zone 6a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00014880. Retrieved from https://blissgarden.com/illinois/zion.