When to plant in Frankfort, IL
USDA Zone 6aFrankfort, Illinois frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
Heads up: the nearest complete-normals station is about 16 km from Frankfort, so your yard's frost dates can differ — a low spot or a paved city center can shift them by a week. Zone 6a means Frankfort sees real winter cold, but a good range of perennials survive; the frost dates above govern when annual vegetables go out.
Frost probability
PARK FOREST · 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 Frankfort’s own odds, recorded at PARK FOREST.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 24 | May 5 | Apr 20 | Sep 27 | Oct 10 | Oct 22 |
| 32°F | May 11 | Apr 23 | Apr 9 | Oct 6 | Oct 20 | Nov 1 |
| 28°F | Apr 27 | Apr 12 | Mar 30 | Oct 18 | Oct 30 | Nov 15 |
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 Frankfort, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 21 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.
Frankfort planting FAQ
When is the last spring frost in Frankfort, IL?
Plan for the last spring frost in Frankfort around April 23 (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 Frankfort, IL?
The first fall frost in Frankfort typically arrives around October 20 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Frankfort in?
Frankfort 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 Frankfort?
There are roughly 180 frost-free days in Frankfort (a moderate growing season), running from the average last frost around April 23 to the first fall frost near October 20.
When should I plant tomatoes in Frankfort?
In Frankfort, start tomato seeds indoors around February 26–March 12, then transplant seedlings outdoors around April 30 once the danger of frost has passed.
Never miss a window in Frankfort
An email when it’s time to start seeds, transplant, and sow — timed to Frankfort’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Mokena · 3 km
- New Lenox · 8 km
- Tinley Park · 9 km
- Matteson · 10 km
- Richton Park · 11 km
- Orland Park · 11 km
- Homer Glen · 13 km
- Manhattan · 13 km
Frost dates recorded at PARK FOREST, 16 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 Frankfort, IL — Frost Dates & Zone 6a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00116616. Retrieved from https://blissgarden.com/illinois/frankfort.