Last spring frost
Apr 15
Frost Dates for Marshall, IL
First fall frost
Oct 19
Growing season
187 days
Hardiness zone
6a
In an average year around Marshall, IL, the last spring frost (32°F) is about Apr 15 and the first fall frost is about Oct 19, giving roughly a 187-day growing season. To be safe most years, wait until Mar 31 before setting out tender plants.
Last spring frost
Dates the last frost of spring typically ends. Plant tender crops after the risk has passed for your comfort level.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | May 15 | Apr 26 | Apr 11 |
| Freeze (32°F) | May 3 | Apr 15 | Mar 31 |
| Hard (28°F) | Apr 20 | Apr 1 | Mar 15 |
| Severe (24°F) | Apr 8 | Mar 23 | Mar 5 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 15 | May 8 | May 3 | Apr 30 | Apr 26 | Apr 22 | Apr 19 | Apr 16 | Apr 11 |
| 32°F | May 3 | Apr 26 | Apr 22 | Apr 18 | Apr 15 | Apr 11 | Apr 7 | Apr 3 | Mar 31 |
| 28°F | Apr 20 | Apr 13 | Apr 8 | Apr 4 | Apr 1 | Mar 30 | Mar 27 | Mar 23 | Mar 15 |
| 24°F | Apr 8 | Apr 1 | Mar 29 | Mar 26 | Mar 23 | Mar 19 | Mar 16 | Mar 11 | Mar 5 |
| 20°F | Mar 29 | Mar 23 | Mar 19 | Mar 16 | Mar 12 | Mar 9 | Mar 5 | Mar 2 | Feb 25 |
| 16°F | Mar 20 | Mar 15 | Mar 11 | Mar 7 | Mar 4 | Mar 1 | Feb 26 | Feb 20 | Feb 11 |
First fall frost
Dates the first frost of fall typically arrives. Count back by a crop's days-to-maturity to know your planting cutoff.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Sep 26 | Oct 10 | Oct 23 |
| Freeze (32°F) | Oct 4 | Oct 19 | Nov 2 |
| Hard (28°F) | Oct 14 | Oct 30 | Nov 14 |
| Severe (24°F) | Oct 25 | Nov 10 | Nov 30 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 26 | Oct 1 | Oct 3 | Oct 6 | Oct 10 | Oct 13 | Oct 15 | Oct 19 | Oct 23 |
| 32°F | Oct 4 | Oct 8 | Oct 13 | Oct 16 | Oct 19 | Oct 22 | Oct 25 | Oct 29 | Nov 2 |
| 28°F | Oct 14 | Oct 19 | Oct 23 | Oct 27 | Oct 30 | Nov 1 | Nov 5 | Nov 8 | Nov 14 |
| 24°F | Oct 25 | Nov 1 | Nov 3 | Nov 7 | Nov 10 | Nov 14 | Nov 18 | Nov 23 | Nov 30 |
| 20°F | Nov 3 | Nov 9 | Nov 13 | Nov 18 | Nov 23 | Nov 26 | Dec 1 | Dec 4 | Dec 12 |
| 16°F | Nov 14 | Nov 22 | Nov 27 | Dec 1 | Dec 4 | Dec 8 | Dec 13 | Dec 19 | Dec 24 |
Growing season is measured at 32°F with about 50% probability. Hardiness zone from the 2023 USDA map; frost normals from NOAA 1991-2020.
Where this data comes from
@endif These dates are computed from the nearest official weather station with long-term records: Terre Haute Indiana State, In, about 9.2 miles away@if(!empty($station['elevation_ft'])), at 507 ft elevation. The further the station and the greater the elevation difference from your yard, the more your local frost timing can vary.
How we calculate these dates
Frost and freeze dates come from the NOAA 1991–2020 U.S. Climate Normals, the National Oceanic and Atmospheric Administration's 30-year averages for each weather station. A date shown at the 50% level is the median: in half of years the frost falls on or before it. The 10% and 90% columns show the early and late ends of the range, so you can plant on the odds you're comfortable with. These are long-term averages, not a forecast for this year - always check your local outlook before planting.
Source: NOAA National Centers for Environmental Information, 1991–2020 Climate Normals (public domain). Harman is not affiliated with or endorsed by NOAA.
Frequently asked questions
When is the last frost in Marshall, IL?
On average, the last spring frost (32°F) around Marshall, IL is about Apr 15. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 31.
When is the first frost in the fall?
The first fall frost around Marshall, IL typically arrives about Oct 19. Count back by a crop's days to maturity to find the latest date you can plant it.
When can I plant tomatoes and other tender crops?
Tender crops like tomatoes, peppers and basil are damaged by frost, so wait until the last spring frost has passed - around Apr 15 on average, or Mar 31 to be safe most years.
How long is the growing season here?
The frost-free growing season (between the last spring and first fall 32°F frost) is about 187 days in a typical year.
Are these dates a forecast for this year?
No. They are 30-year averages from the NOAA 1991–2020 Climate Normals, not a prediction for the current year. Use them for planning and always check your local weather forecast before planting or protecting crops.
Local weather for 62423 Planting calendar → Illinois frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026