Last spring frost
Apr 26
Frost Dates for Cambridge, IL
First fall frost
Oct 12
Growing season
166 days
Hardiness zone
5b
In an average year around Cambridge, IL, the last spring frost (32°F) is about Apr 26 and the first fall frost is about Oct 12, giving roughly a 166-day growing season. To be safe most years, wait until Apr 12 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 20 | May 5 | Apr 23 |
| Freeze (32°F) | May 11 | Apr 26 | Apr 12 |
| Hard (28°F) | Apr 30 | Apr 16 | Apr 3 |
| Severe (24°F) | Apr 20 | Apr 5 | Mar 23 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 20 | May 15 | May 12 | May 8 | May 5 | May 3 | Apr 30 | Apr 27 | Apr 23 |
| 32°F | May 11 | May 5 | May 2 | Apr 29 | Apr 26 | Apr 24 | Apr 21 | Apr 17 | Apr 12 |
| 28°F | Apr 30 | Apr 25 | Apr 22 | Apr 19 | Apr 16 | Apr 12 | Apr 9 | Apr 6 | Apr 3 |
| 24°F | Apr 20 | Apr 15 | Apr 11 | Apr 8 | Apr 5 | Apr 3 | Apr 1 | Mar 28 | Mar 23 |
| 20°F | Apr 9 | Apr 4 | Apr 2 | Mar 31 | Mar 27 | Mar 23 | Mar 19 | Mar 15 | Mar 9 |
| 16°F | Mar 31 | Mar 27 | Mar 23 | Mar 19 | Mar 15 | Mar 13 | Mar 9 | Mar 6 | Mar 1 |
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 17 | Oct 2 | Oct 13 |
| Freeze (32°F) | Sep 25 | Oct 12 | Oct 24 |
| Hard (28°F) | Oct 7 | Oct 22 | Nov 3 |
| Severe (24°F) | Oct 20 | Nov 1 | Nov 15 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 17 | Sep 23 | Sep 27 | Sep 30 | Oct 2 | Oct 4 | Oct 7 | Oct 10 | Oct 13 |
| 32°F | Sep 25 | Oct 2 | Oct 6 | Oct 10 | Oct 12 | Oct 14 | Oct 16 | Oct 19 | Oct 24 |
| 28°F | Oct 7 | Oct 13 | Oct 17 | Oct 20 | Oct 22 | Oct 24 | Oct 27 | Oct 30 | Nov 3 |
| 24°F | Oct 20 | Oct 24 | Oct 28 | Oct 30 | Nov 1 | Nov 3 | Nov 7 | Nov 10 | Nov 15 |
| 20°F | Oct 31 | Nov 3 | Nov 6 | Nov 9 | Nov 12 | Nov 14 | Nov 17 | Nov 21 | Nov 27 |
| 16°F | Nov 7 | Nov 11 | Nov 15 | Nov 18 | Nov 21 | Nov 24 | Nov 28 | Dec 1 | Dec 7 |
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: Galva, Il, about 10.3 miles away@if(!empty($station['elevation_ft'])), at 810 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 Cambridge, IL?
On average, the last spring frost (32°F) around Cambridge, IL is about Apr 26. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 12.
When is the first frost in the fall?
The first fall frost around Cambridge, IL typically arrives about Oct 12. 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 26 on average, or Apr 12 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 166 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 61238 Planting calendar → Illinois frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026