Last spring frost
Apr 23
Frost Dates for Hancock, IA
First fall frost
Oct 14
Growing season
174 days
Hardiness zone
5b
In an average year around Hancock, IA, the last spring frost (32°F) is about Apr 23 and the first fall frost is about Oct 14, giving roughly a 174-day growing season. To be safe most years, wait until Apr 10 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 14 | May 2 | Apr 20 |
| Freeze (32°F) | May 5 | Apr 23 | Apr 10 |
| Hard (28°F) | Apr 28 | Apr 15 | Mar 31 |
| Severe (24°F) | Apr 21 | Apr 6 | Mar 20 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 14 | May 10 | May 7 | May 4 | May 2 | Apr 30 | Apr 27 | Apr 24 | Apr 20 |
| 32°F | May 5 | May 1 | Apr 29 | Apr 26 | Apr 23 | Apr 21 | Apr 18 | Apr 15 | Apr 10 |
| 28°F | Apr 28 | Apr 24 | Apr 21 | Apr 18 | Apr 15 | Apr 11 | Apr 8 | Apr 5 | Mar 31 |
| 24°F | Apr 21 | Apr 16 | Apr 12 | Apr 9 | Apr 6 | Apr 3 | Mar 31 | Mar 28 | Mar 20 |
| 20°F | Apr 13 | Apr 7 | Apr 3 | Mar 31 | Mar 29 | Mar 25 | Mar 20 | Mar 15 | Mar 9 |
| 16°F | Apr 3 | Mar 30 | Mar 25 | Mar 20 | Mar 16 | Mar 13 | Mar 9 | Mar 6 | Mar 2 |
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 20 | Oct 4 | Oct 18 |
| Freeze (32°F) | Sep 30 | Oct 14 | Oct 27 |
| Hard (28°F) | Oct 11 | Oct 25 | Nov 6 |
| Severe (24°F) | Oct 20 | Nov 2 | Nov 16 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 20 | Sep 26 | Sep 29 | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 14 | Oct 18 |
| 32°F | Sep 30 | Oct 4 | Oct 8 | Oct 12 | Oct 14 | Oct 17 | Oct 21 | Oct 23 | Oct 27 |
| 28°F | Oct 11 | Oct 15 | Oct 19 | Oct 22 | Oct 25 | Oct 27 | Oct 30 | Nov 1 | Nov 6 |
| 24°F | Oct 20 | Oct 25 | Oct 29 | Oct 31 | Nov 2 | Nov 4 | Nov 8 | Nov 11 | Nov 16 |
| 20°F | Oct 27 | Nov 1 | Nov 4 | Nov 7 | Nov 10 | Nov 13 | Nov 16 | Nov 21 | Nov 28 |
| 16°F | Nov 3 | Nov 8 | Nov 12 | Nov 16 | Nov 20 | Nov 23 | Nov 28 | Dec 1 | Dec 5 |
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: Oakland, Ia, about 5.6 miles away@if(!empty($station['elevation_ft'])), at 1,260 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 Hancock, IA?
On average, the last spring frost (32°F) around Hancock, IA is about Apr 23. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 10.
When is the first frost in the fall?
The first fall frost around Hancock, IA typically arrives about Oct 14. 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 23 on average, or Apr 10 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 174 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 51536 Planting calendar → Iowa frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026