When to plant in Cahokia Heights, IL
USDA Zone 7aEverything below — frost dates, hardiness zone, and what to plant when in Cahokia Heights, Illinois — is derived from the closest NOAA station with complete climate normals.
In zone 7a, Cahokia Heights supports a wide range of perennials year-round; the frost dates above are what set your annual vegetable timing.
Frost probability
CAHOKIA ST LOUIS 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 Cahokia Heights’s own odds, recorded at CAHOKIA ST LOUIS AP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 4 | Apr 19 | Apr 4 | Oct 3 | Oct 17 | Oct 28 |
| 32°F | Apr 23 | Apr 8 | Mar 23 | Oct 12 | Oct 26 | Nov 7 |
| 28°F | Apr 12 | Mar 28 | Mar 10 | Oct 24 | Nov 6 | Nov 24 |
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 Cahokia Heights, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 12 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.
Cahokia Heights planting FAQ
When is the last spring frost in Cahokia Heights, IL?
Cahokia Heights's average last spring frost falls near April 8 — 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 Cahokia Heights, IL?
In Cahokia Heights, the first 32°F freeze of fall lands around October 26 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Cahokia Heights in?
Cahokia Heights 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 Cahokia Heights?
Cahokia Heights has about 201 frost-free days — a moderate growing season — between the average last spring frost (April 8) and first fall frost (October 26).
When should I plant tomatoes in Cahokia Heights?
For Cahokia Heights, sow tomatoes indoors about February 11–February 25 and move the seedlings out around April 15, after the last spring frost.
Never miss a window in Cahokia Heights
An email when it’s time to start seeds, transplant, and sow — timed to Cahokia Heights’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- East St. Louis · 5 km
- St. Louis · 11 km
- Lemay · 12 km
- Fairview Heights · 13 km
- Columbia · 14 km
- Swansea · 15 km
- Affton · 15 km
- Belleville · 16 km
Frost dates recorded at CAHOKIA ST LOUIS AP, 0 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 Cahokia Heights, IL — Frost Dates & Zone 7a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00003960. Retrieved from https://blissgarden.com/illinois/cahokia-heights.