When to plant in Herrin, IL
USDA Zone 7aEverything below — frost dates, hardiness zone, and what to plant when in Herrin, Illinois — is derived from the closest NOAA station with complete climate normals.
Zone 7a means many perennials and even some tender shrubs overwinter in Herrin, while your frost dates still decide when annuals go out.
Frost probability
CARBONDALE SEWAGE PLT · 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 Herrin’s own odds, recorded at CARBONDALE SEWAGE PLT.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 5 | Apr 22 | Apr 5 | Sep 30 | Oct 13 | Oct 25 |
| 32°F | Apr 25 | Apr 9 | Mar 25 | Oct 10 | Oct 22 | Nov 2 |
| 28°F | Apr 14 | Mar 29 | Mar 11 | Oct 19 | Nov 1 | Nov 18 |
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 Herrin, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 25 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.
Herrin planting FAQ
When is the last spring frost in Herrin, IL?
On average, the last spring frost in Herrin is around April 9 (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 Herrin, IL?
Expect Herrin's first fall frost near October 22 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Herrin in?
Herrin is in USDA hardiness zone 7a. In zone 7a, winters are moderate — most common vegetables grow well in season.
How long is the growing season in Herrin?
There are roughly 196 frost-free days in Herrin (a moderate growing season), running from the average last frost around April 9 to the first fall frost near October 22.
When should I plant tomatoes in Herrin?
In Herrin, start tomato seeds indoors around February 12–February 26, then transplant seedlings outdoors around April 16 once the danger of frost has passed.
Never miss a window in Herrin
An email when it’s time to start seeds, transplant, and sow — timed to Herrin’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Marion · 11 km
- Carbondale · 19 km
- Mount Vernon · 58 km
- Cape Girardeau · 72 km
- Jackson · 72 km
- Centralia · 81 km
- Paducah · 88 km
- Sikeston · 113 km
Frost dates recorded at CARBONDALE SEWAGE PLT, 14 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 Herrin, IL — Frost Dates & Zone 7a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00111265. Retrieved from https://blissgarden.com/illinois/herrin.