When to plant in Belvidere, IL
USDA Zone 5bHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Belvidere, Illinois — all computed from Belvidere's nearest NOAA weather station.
Belvidere's nearest full-normals station sits about 19 km out, so treat these as a close estimate — local microclimate can nudge your first and last frost. In zone 5b, Belvidere gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
The average first fall frost in Belvidere is now 6 days later than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
ROCKFORD GTR ROCKFORD 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 Belvidere’s own odds, recorded at ROCKFORD GTR ROCKFORD AP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 19 | May 4 | Apr 21 | Sep 23 | Oct 6 | Oct 20 |
| 32°F | May 8 | Apr 24 | Apr 10 | Oct 2 | Oct 17 | Oct 30 |
| 28°F | Apr 27 | Apr 13 | Mar 31 | Oct 14 | Oct 28 | Nov 10 |
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 Belvidere, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 29 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.
Belvidere planting FAQ
When is the last spring frost in Belvidere, IL?
On average, the last spring frost in Belvidere is around April 24 (50% probability at 32°F, from 1991–2020 NOAA normals). Wait until after this date to set out tender plants like tomatoes and peppers.
When is the first fall frost in Belvidere, IL?
In Belvidere, the first 32°F freeze of fall lands around October 17 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Belvidere in?
Belvidere 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 Belvidere?
Belvidere has about 176 frost-free days — a moderate growing season — between the average last spring frost (April 24) and first fall frost (October 17).
When should I plant tomatoes in Belvidere?
For Belvidere, sow tomatoes indoors about February 27–March 13 and move the seedlings out around May 1, after the last spring frost.
Never miss a window in Belvidere
An email when it’s time to start seeds, transplant, and sow — timed to Belvidere’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Loves Park · 12 km
- Rockford · 14 km
- Machesney Park · 16 km
- Roscoe · 20 km
- Beloit · 31 km
- Sycamore · 35 km
- Woodstock · 38 km
- Huntley · 39 km
Frost dates recorded at ROCKFORD GTR ROCKFORD AP, 19 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 Belvidere, IL — Frost Dates & Zone 5b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00094822. Retrieved from https://blissgarden.com/illinois/belvidere.