When to plant in Granite City, IL
USDA Zone 7aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Granite City, Illinois — all computed from Granite City's nearest NOAA weather station.
Granite City's nearest full-normals station sits about 15 km out, so treat these as a close estimate — local microclimate can nudge your first and last frost. In zone 7a, Granite City supports a wide range of perennials year-round; the frost dates above are what set your annual vegetable timing.
Frost probability
ALTON - MELVIN PRICE 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 Granite City’s own odds, recorded at ALTON - MELVIN PRICE L&D.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 1 | Apr 14 | Mar 31 | Oct 12 | Oct 27 | Nov 8 |
| 32°F | Apr 19 | Apr 4 | Mar 18 | Oct 25 | Nov 5 | Nov 21 |
| 28°F | Apr 9 | Mar 25 | Mar 6 | Nov 2 | Nov 16 | Dec 1 |
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 Granite City, 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.
Granite City planting FAQ
When is the last spring frost in Granite City, IL?
Plan for the last spring frost in Granite City around April 4 (the date it has a 50% chance of a 32°F freeze). Anything frost-sensitive should go out after it.
When is the first fall frost in Granite City, IL?
In Granite City, the first 32°F freeze of fall lands around November 5 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Granite City in?
Granite City is in USDA hardiness zone 7a. In zone 7a, winters are moderate — most common vegetables grow well in season.
How long is the growing season in Granite City?
Granite City has about 215 frost-free days — a long growing season — between the average last spring frost (April 4) and first fall frost (November 5).
When should I plant tomatoes in Granite City?
For Granite City, sow tomatoes indoors about February 7–February 21 and move the seedlings out around April 11, after the last spring frost.
Never miss a window in Granite City
An email when it’s time to start seeds, transplant, and sow — timed to Granite City’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Bellefontaine Neighbors · 9 km
- Spanish Lake · 10 km
- Collinsville · 12 km
- Jennings · 12 km
- East St. Louis · 13 km
- Glen Carbon · 13 km
- Edwardsville · 14 km
- St. Louis · 15 km
Frost dates recorded at ALTON - MELVIN PRICE L&D, 15 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 Granite City, IL — Frost Dates & Zone 7a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00110137. Retrieved from https://blissgarden.com/illinois/granite-city.