Last spring frost
Apr 24
Frost Dates for Hillsboro, OH
First fall frost
Oct 20
Growing season
178 days
Hardiness zone
6b
In an average year around Hillsboro, OH, the last spring frost (32°F) is about Apr 24 and the first fall frost is about Oct 20, giving roughly a 178-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 20 | May 4 | Apr 21 |
| Freeze (32°F) | May 11 | Apr 24 | Apr 10 |
| Hard (28°F) | Apr 29 | Apr 12 | Mar 31 |
| Severe (24°F) | Apr 17 | Apr 2 | Mar 18 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 20 | May 14 | May 10 | May 7 | May 4 | Apr 30 | Apr 28 | Apr 26 | Apr 21 |
| 32°F | May 11 | May 5 | Apr 30 | Apr 27 | Apr 24 | Apr 21 | Apr 18 | Apr 15 | Apr 10 |
| 28°F | Apr 29 | Apr 22 | Apr 18 | Apr 16 | Apr 12 | Apr 9 | Apr 6 | Apr 3 | Mar 31 |
| 24°F | Apr 17 | Apr 12 | Apr 8 | Apr 5 | Apr 2 | Mar 31 | Mar 29 | Mar 23 | Mar 18 |
| 20°F | Apr 6 | Apr 2 | Mar 31 | Mar 28 | Mar 24 | Mar 20 | Mar 17 | Mar 12 | Mar 5 |
| 16°F | Mar 31 | Mar 24 | Mar 20 | Mar 17 | Mar 14 | Mar 9 | Mar 5 | Mar 1 | Feb 22 |
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 27 | Oct 10 | Oct 20 |
| Freeze (32°F) | Oct 6 | Oct 20 | Nov 1 |
| Hard (28°F) | Oct 17 | Nov 1 | Nov 13 |
| Severe (24°F) | Oct 31 | Nov 10 | Nov 28 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 27 | Oct 1 | Oct 4 | Oct 6 | Oct 10 | Oct 12 | Oct 14 | Oct 16 | Oct 20 |
| 32°F | Oct 6 | Oct 12 | Oct 15 | Oct 18 | Oct 20 | Oct 22 | Oct 25 | Oct 27 | Nov 1 |
| 28°F | Oct 17 | Oct 22 | Oct 25 | Oct 29 | Nov 1 | Nov 2 | Nov 5 | Nov 8 | Nov 13 |
| 24°F | Oct 31 | Nov 2 | Nov 4 | Nov 7 | Nov 10 | Nov 13 | Nov 17 | Nov 21 | Nov 28 |
| 20°F | Nov 6 | Nov 10 | Nov 13 | Nov 17 | Nov 20 | Nov 25 | Nov 29 | Dec 3 | Dec 10 |
| 16°F | Nov 13 | Nov 18 | Nov 23 | Nov 27 | Dec 1 | Dec 5 | Dec 10 | Dec 17 | Dec 25 |
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: Hillsboro, Oh, about 5.5 miles away@if(!empty($station['elevation_ft'])), at 953 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 Hillsboro, OH?
On average, the last spring frost (32°F) around Hillsboro, OH is about Apr 24. 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 Hillsboro, OH typically arrives about Oct 20. 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 24 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 178 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 45133 Planting calendar → Ohio frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026