When to plant in Sterling, IL
USDA Zone 5bHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Sterling, Illinois — all computed from Sterling's nearest NOAA weather station.
These dates come from a station roughly 16 km away, the closest with full normals; terrain around Sterling (elevation, water, pavement) can move your real frost dates a few days either way. In zone 5b, Sterling gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
The average first fall frost in Sterling is now 8 days later than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
DIXON 1W · 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 Sterling’s own odds, recorded at DIXON 1W.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 16 | May 2 | Apr 18 | Sep 24 | Oct 9 | Oct 22 |
| 32°F | May 5 | Apr 21 | Apr 7 | Oct 4 | Oct 19 | Oct 30 |
| 28°F | Apr 26 | Apr 10 | Mar 27 | Oct 17 | Oct 30 | Nov 12 |
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 Sterling, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 27 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.
Sterling planting FAQ
When is the last spring frost in Sterling, IL?
On average, the last spring frost in Sterling is around April 21 (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 Sterling, IL?
The first fall frost in Sterling typically arrives around October 19 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Sterling in?
Sterling 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 Sterling?
Sterling has about 181 frost-free days — a moderate growing season — between the average last spring frost (April 21) and first fall frost (October 19).
When should I plant tomatoes in Sterling?
For Sterling, sow tomatoes indoors about February 24–March 10 and move the seedlings out around April 28, after the last spring frost.
Never miss a window in Sterling
An email when it’s time to start seeds, transplant, and sow — timed to Sterling’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Dixon · 19 km
- Clinton · 46 km
- Freeport · 55 km
- Kewanee · 65 km
- East Moline · 65 km
- Bettendorf · 70 km
- Rockford · 73 km
- Moline · 75 km
Frost dates recorded at DIXON 1W, 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 Sterling, IL — Frost Dates & Zone 5b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00112348. Retrieved from https://blissgarden.com/illinois/sterling.