When to plant in Jacksonville, IL
USDA Zone 6aEverything below — frost dates, hardiness zone, and what to plant when in Jacksonville, Illinois — is derived from the closest NOAA station with complete climate normals.
In zone 6a, Jacksonville gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
Frost probability
JACKSONVILLE 2 · 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 Jacksonville’s own odds, recorded at JACKSONVILLE 2.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 11 | Apr 27 | Apr 14 | Sep 27 | Oct 12 | Oct 23 |
| 32°F | May 1 | Apr 17 | Apr 3 | Oct 9 | Oct 21 | Nov 1 |
| 28°F | Apr 21 | Apr 6 | Mar 22 | Oct 18 | Oct 31 | 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 Jacksonville, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 22 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.
Jacksonville planting FAQ
When is the last spring frost in Jacksonville, IL?
Jacksonville's average last spring frost falls near April 17 — 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 Jacksonville, IL?
Expect Jacksonville'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 Jacksonville in?
Jacksonville 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 Jacksonville?
Jacksonville has about 187 frost-free days — a moderate growing season — between the average last spring frost (April 17) and first fall frost (October 21).
When should I plant tomatoes in Jacksonville?
For Jacksonville, sow tomatoes indoors about February 20–March 6 and move the seedlings out around April 24, after the last spring frost.
Never miss a window in Jacksonville
An email when it’s time to start seeds, transplant, and sow — timed to Jacksonville’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Chatham · 47 km
- Springfield · 51 km
- Taylorville · 81 km
- Godfrey · 86 km
- Lincoln · 87 km
- Macomb · 91 km
- Alton · 92 km
- Canton · 94 km
Frost dates recorded at JACKSONVILLE 2, 2 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 Jacksonville, IL — Frost Dates & Zone 6a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00114447. Retrieved from https://blissgarden.com/illinois/jacksonville.