Frost dates for 61079Shirland, IL
The average last spring frost in Shirland is May 1 and the average first fall frost is October 12, giving a typical growing season of about 162 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 1
- Average first fall frost
- Oct 12
- Growing season
- 162 days
Safer after May 16 (1-in-10 risk)
Possible by Sep 28 (1-in-10 risk)
Last frost typically in 182 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | Apr 29 · May 11 · May 27 | Sep 21 · Oct 1 · Oct 14 | 143 days | 100% |
| Frost / freeze (32°F) | Apr 17 · May 1 · May 16 | Sep 28 · Oct 12 · Oct 24 | 162 days | 100% |
| Hard freeze (28°F) | Apr 4 · Apr 20 · May 4 | Oct 9 · Oct 23 · Nov 4 | 186 days | 100% |
Planting calendar for Shirland
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Mar 31 – Jun 6 |
| Tomatoes | Transplant outdoors | May 17 – Jun 22 |
| Peppers | Start seeds indoors | Mar 31 – May 1 |
| Peppers | Transplant outdoors | May 31 – Jul 1 |
| Eggplant | Start seeds indoors | Apr 17 – May 16 |
| Eggplant | Transplant outdoors | May 31 – Jul 1 |
| Cucumbers | Sow outdoors | May 31 – Jul 2 |
| Summer squash | Sow outdoors | May 17 – Jul 1 |
| Winter squash & pumpkins | Sow outdoors | May 31 – Jul 1 |
| Snap beans | Sow outdoors | May 17 – Jul 25 |
| Sweet corn | Sow outdoors | May 17 – Jun 22 |
| Watermelon & cantaloupe | Sow outdoors | May 31 – Jul 1 |
| Okra | Sow outdoors | May 24 – Jun 16 |
| Peas | Sow outdoors (spring) | Mar 31 – May 16 |
| Potatoes | Plant outdoors (spring) | Mar 31 – May 31 |
| Onions | Start seeds indoors (spring) | Feb 17 – Mar 16 |
| Onions | Transplant outdoors (spring) | Apr 17 – May 16 |
| Broccoli | Start seeds indoors (spring) | Mar 13 – Apr 16 |
| Broccoli | Transplant outdoors (spring) | Apr 17 – May 16 |
| Broccoli | Start seeds indoors (fall) | Jun 12 – Jun 22 |
| Broccoli | Transplant outdoors (fall) | Jul 12 – Jul 23 |
| Cabbage | Start seeds indoors (spring) | Mar 3 – Mar 31 |
| Cabbage | Transplant outdoors (spring) | Mar 31 – May 1 |
| Cabbage | Start seeds indoors (fall) | Jun 2 – Jul 2 |
| Cabbage | Transplant outdoors (fall) | Jul 2 – Aug 2 |
| Leaf lettuce | Sow outdoors (spring) | Mar 31 – Jun 16 |
| Leaf lettuce | Sow outdoors (fall) | Jul 2 – Aug 18 |
| Spinach | Sow outdoors (spring) | Mar 24 – May 7 |
| Spinach | Sow outdoors (fall) | Jul 19 – Aug 23 |
| Radishes | Sow outdoors (spring) | Mar 31 – May 21 |
| Radishes | Sow outdoors (fall) | Jul 2 – Sep 2 |
| Kale | Sow outdoors (spring) | Apr 17 – May 7 |
| Kale | Sow outdoors (fall) | Jun 25 – Aug 2 |
| Carrots | Sow outdoors (spring) | May 1 – Jun 16 |
| Carrots | Sow outdoors (fall) | Jun 2 – Jul 18 |
| Garlic | Plant outdoors (fall) | Oct 2 – Nov 2 |
Where these dates come from
ZIP code 61079 is matched to the NOAA station Beloit, WI, 15.2 km away, at 788 ft elevation (53 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Beloit, WI (used) | 788 ft | May 1 | Oct 12 |
| Afton - Janesville Wwtp, WI | 762 ft | Apr 26 | Oct 15 |
| Brodhead Wwtp, WI | 780 ft | Apr 29 | Oct 12 |
| Clinton Wwtp, WI | 924 ft | Apr 30 | Oct 10 |
Frost dates near Shirland
- Rockton, IL 61072 · last May 1, first Oct 12
- Durand, IL 61024 · last Apr 29, first Oct 12
- Rockford, IL 61106 · last Apr 24, first Oct 17
- Loves Park, IL 61130 · last Apr 24, first Oct 17
- South Beloit, IL 61080 · last May 1, first Oct 12
- Beloit, WI 53512 · last May 1, first Oct 12
- Machesney Park, IL 61115 · last Apr 24, first Oct 17
- Roscoe, IL 61073 · last May 1, first Oct 12
Frequently asked questions
- When is the last frost in Shirland, IL?
- For ZIP code 61079, the average last spring frost (32°F) is May 1, based on NOAA 1991-2020 climate normals for the Beloit, WI weather station. There is a 1-in-10 chance of a frost after May 16.
- When is the first frost in Shirland, IL?
- The average first fall frost (32°F) is October 12. There is a 1-in-10 chance of frost by September 28, so tender plants are at risk from that point on.
- How long is the growing season in 61079?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 162 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.