When to plant in Bourbonnais, IL
USDA Zone 5bEverything below — frost dates, hardiness zone, and what to plant when in Bourbonnais, Illinois — is derived from the closest NOAA station with complete climate normals.
Zone 5b means Bourbonnais sees real winter cold, but a good range of perennials survive; the frost dates above govern when annual vegetables go out.
Frost probability
KANKAKEE METRO WASTEWATER · 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 Bourbonnais’s own odds, recorded at KANKAKEE METRO WASTEWATER.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 14 | Apr 30 | Apr 16 | Oct 1 | Oct 14 | Oct 27 |
| 32°F | May 3 | Apr 19 | Apr 5 | Oct 12 | Oct 24 | Nov 5 |
| 28°F | Apr 22 | Apr 6 | Mar 21 | Oct 23 | Nov 4 | Nov 19 |
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 Bourbonnais, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 40 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.
Bourbonnais planting FAQ
When is the last spring frost in Bourbonnais, IL?
Bourbonnais's average last spring frost falls near April 19 — 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 Bourbonnais, IL?
Expect Bourbonnais's first fall frost near October 24 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Bourbonnais in?
Bourbonnais is in USDA hardiness zone 5b. In zone 5b, winters are cold — pick cold-hardy varieties and protect tender crops.
How long is the growing season in Bourbonnais?
There are roughly 188 frost-free days in Bourbonnais (a moderate growing season), running from the average last frost around April 19 to the first fall frost near October 24.
When should I plant tomatoes in Bourbonnais?
In Bourbonnais, start tomato seeds indoors around February 22–March 8, then transplant seedlings outdoors around April 26 once the danger of frost has passed.
Never miss a window in Bourbonnais
An email when it’s time to start seeds, transplant, and sow — timed to Bourbonnais’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Bradley · 3 km
- Kankakee · 9 km
- Manhattan · 28 km
- Richton Park · 35 km
- Frankfort · 36 km
- Park Forest · 37 km
- New Lenox · 37 km
- Matteson · 38 km
Frost dates recorded at KANKAKEE METRO WASTEWATER, 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 Bourbonnais, IL — Frost Dates & Zone 5b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00114603. Retrieved from https://blissgarden.com/illinois/bourbonnais.