Frost dates for 61368Tiskilwa, IL
The average last spring frost in Tiskilwa is April 22 and the average first fall frost is October 17, giving a typical growing season of about 177 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 22
- Average first fall frost
- Oct 17
- Growing season
- 177 days
Safer after May 7 (1-in-10 risk)
Possible by Oct 3 (1-in-10 risk)
Last frost typically in 174 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 19 · May 3 · May 17 | Sep 23 · Oct 6 · Oct 20 | 155 days | 100% |
| Frost / freeze (32°F) | Apr 9 · Apr 22 · May 7 | Oct 3 · Oct 17 · Oct 29 | 177 days | 100% |
| Hard freeze (28°F) | Mar 31 · Apr 12 · Apr 26 | Oct 14 · Oct 27 · Nov 9 | 197 days | 100% |
Planting calendar for Tiskilwa
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 22 – May 28 |
| Tomatoes | Transplant outdoors | May 8 – Jun 27 |
| Peppers | Start seeds indoors | Mar 22 – Apr 22 |
| Peppers | Transplant outdoors | May 22 – Jun 22 |
| Eggplant | Start seeds indoors | Apr 8 – May 7 |
| Eggplant | Transplant outdoors | May 22 – Jun 22 |
| Cucumbers | Sow outdoors | May 22 – Jul 7 |
| Summer squash | Sow outdoors | May 8 – Jun 22 |
| Winter squash & pumpkins | Sow outdoors | May 22 – Jun 22 |
| Snap beans | Sow outdoors | May 8 – Jul 30 |
| Sweet corn | Sow outdoors | May 8 – Jun 27 |
| Watermelon & cantaloupe | Sow outdoors | May 22 – Jun 22 |
| Okra | Sow outdoors | May 15 – Jun 7 |
| Peas | Sow outdoors (spring) | Mar 22 – May 7 |
| Potatoes | Plant outdoors (spring) | Mar 22 – May 22 |
| Onions | Start seeds indoors (spring) | Feb 8 – Mar 7 |
| Onions | Transplant outdoors (spring) | Apr 8 – May 7 |
| Broccoli | Start seeds indoors (spring) | Mar 4 – Apr 7 |
| Broccoli | Transplant outdoors (spring) | Apr 8 – May 7 |
| Broccoli | Start seeds indoors (fall) | Jun 17 – Jun 27 |
| Broccoli | Transplant outdoors (fall) | Jul 17 – Jul 28 |
| Cabbage | Start seeds indoors (spring) | Feb 22 – Mar 22 |
| Cabbage | Transplant outdoors (spring) | Mar 22 – Apr 22 |
| Cabbage | Start seeds indoors (fall) | Jun 7 – Jul 7 |
| Cabbage | Transplant outdoors (fall) | Jul 7 – Aug 7 |
| Leaf lettuce | Sow outdoors (spring) | Mar 22 – Jun 7 |
| Leaf lettuce | Sow outdoors (fall) | Jul 7 – Aug 23 |
| Spinach | Sow outdoors (spring) | Mar 15 – Apr 28 |
| Spinach | Sow outdoors (fall) | Jul 24 – Aug 28 |
| Radishes | Sow outdoors (spring) | Mar 22 – May 12 |
| Radishes | Sow outdoors (fall) | Jul 7 – Sep 7 |
| Kale | Sow outdoors (spring) | Apr 8 – Apr 28 |
| Kale | Sow outdoors (fall) | Jun 30 – Aug 7 |
| Carrots | Sow outdoors (spring) | Apr 22 – Jun 7 |
| Carrots | Sow outdoors (fall) | Jun 7 – Jul 23 |
| Garlic | Plant outdoors (fall) | Oct 7 – Nov 7 |
Where these dates come from
ZIP code 61368 is matched to the NOAA station Princeton, IL, 9.8 km away, at 697 ft elevation (139 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Princeton, IL (used) | 697 ft | Apr 22 | Oct 17 |
| Hennepin Wtr Trmt Plt, IL | 460 ft | Apr 24 | Oct 17 |
| Hennepin, IL | 515 ft | Apr 18 | Oct 22 |
| Lacon, IL | 458 ft | Apr 20 | Oct 17 |
Frost dates near Tiskilwa
- Princeton, IL 61356 · last Apr 22, first Oct 17
- Wyanet, IL 61379 · last Apr 22, first Oct 17
- Bureau, IL 61315 · last Apr 24, first Oct 17
- Putnam, IL 61560 · last Apr 24, first Oct 17
- Buda, IL 61314 · last Apr 24, first Oct 17
- Depue, IL 61322 · last Apr 24, first Oct 17
- Hennepin, IL 61327 · last Apr 24, first Oct 17
- Dover, IL 61323 · last Apr 22, first Oct 17
Frequently asked questions
- When is the last frost in Tiskilwa, IL?
- For ZIP code 61368, the average last spring frost (32°F) is April 22, based on NOAA 1991-2020 climate normals for the Princeton, IL weather station. There is a 1-in-10 chance of a frost after May 7.
- When is the first frost in Tiskilwa, IL?
- The average first fall frost (32°F) is October 17. There is a 1-in-10 chance of frost by October 3, so tender plants are at risk from that point on.
- How long is the growing season in 61368?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 177 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.