USDA Hardiness Zone 6b
Frost Dates for 45123 — Greenfield, Ohio
NOAA 1991–2020 normals from Washington Court House, OH (957 ft), 13 miles north.
Updated
In Greenfield, the last spring frost (32°F) is around April 23 in half of years and has passed by May 8 in nine years out of ten. The first fall frost comes around October 21, as early as October 8 one year in ten, leaving a typical freeze-free season of 181 days (NOAA, Washington Court House, OH).
- Last spring frost
- April 23
- First fall frost
- October 21
- Growing season
- 181 days
- Hardiness zone
- 6b
50% probability
50% probability
freeze-free, 50%
-5 to 0°F (-20.6 to -17.8°C) coldest night
- First snow
- December 10
- Last snow
- March 13
- Winters with snow
- 100%
- Snow per year
- 18.3"
median, 1991–2020
median, 1991–2020
15 of 15 observed
NOAA normal
Frost risk by date in Greenfield
Half of springs at Washington Court House, OH see their last 32°F night by April 23; only one in ten is past it by April 10, and one in ten still has one after May 8. Planting tender crops after April 29 leaves a 30% risk of a frost on them, after May 2 20%, and after May 8 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 77% of the 148 Ohio stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 21 in half of years, as early as October 8 one year in ten, and holds off past October 31 one year in ten. A hard freeze of 28°F follows 11 days later, around November 1; in spring the one-in-ten date for 28°F is April 25, 13 days before the 32°F one. The freeze-free season lasts 181 days in a typical year, longer than at 53% of the 148 Ohio stations; it reaches 198 days one year in ten and falls short of 162 one year in ten. On average 115 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 9 days longer, to about May 2, and return around October 10. Severe cold of 16°F or below comes every winter, usually between December 4 and March 10.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 19 | Apr 23 | Apr 27 | Apr 30 | May 2 | May 5 | May 9 | May 13 | May 19 |
| 32°F | Apr 10 | Apr 15 | Apr 18 | Apr 21 | Apr 23 | Apr 26 | Apr 29 | May 2 | May 8 |
| 28°F | Mar 29 | Apr 2 | Apr 5 | Apr 8 | Apr 11 | Apr 14 | Apr 17 | Apr 20 | Apr 25 |
| 24°F | Mar 17 | Mar 22 | Mar 26 | Mar 29 | Apr 1 | Apr 3 | Apr 5 | Apr 9 | Apr 14 |
| 20°F | Mar 4 | Mar 10 | Mar 15 | Mar 18 | Mar 21 | Mar 24 | Mar 27 | Mar 31 | Apr 4 |
| 16°F | Feb 19 | Feb 27 | Mar 3 | Mar 7 | Mar 10 | Mar 15 | Mar 18 | Mar 22 | Mar 28 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 27 | Oct 2 | Oct 5 | Oct 7 | Oct 10 | Oct 12 | Oct 14 | Oct 18 | Oct 22 |
| 32°F | Oct 8 | Oct 13 | Oct 16 | Oct 18 | Oct 21 | Oct 23 | Oct 25 | Oct 28 | Oct 31 |
| 28°F | Oct 20 | Oct 24 | Oct 28 | Oct 30 | Nov 1 | Nov 3 | Nov 5 | Nov 9 | Nov 14 |
| 24°F | Oct 31 | Nov 2 | Nov 4 | Nov 7 | Nov 11 | Nov 14 | Nov 17 | Nov 22 | Nov 28 |
| 20°F | Nov 6 | Nov 11 | Nov 15 | Nov 18 | Nov 22 | Nov 26 | Nov 30 | Dec 3 | Dec 8 |
| 16°F | Nov 14 | Nov 20 | Nov 26 | Nov 30 | Dec 4 | Dec 8 | Dec 12 | Dec 19 | Dec 26 |
Freeze probabilities 1991–2020 at Washington Court House, OH, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.
Frost risk on any date in 45123 →Compare Greenfield with another place →
Weather by month in Greenfield
July is the warmest month at Washington Court House, OH, averaging 84°F by day and 63°F at night; January is the coldest at 36°F and 20°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 25% of years.
Warmth for growing adds up to 3,244 growing degree days a year (base 50°F), more than at 51% of the 148 Ohio stations. 36% of them (1,162) have built up by the end of June, and July adds the most, 719. Precipitation totals 41.0 inches a year, most in May (4.5") and least in February (2.5"); May to September bring 46% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 36 | 20 | 3.0 | 100% | 27 | 3 |
| Feb | 40 | 22 | 2.5 | 100% | 22 | 4 |
| Mar | 50 | 30 | 3.8 | 100% | 18 | 38 |
| Apr | 64 | 40 | 4.1 | 99% | 6 | 138 |
| May | 73 | 51 | 4.5 | 25% | <1 | 373 |
| Jun | 81 | 60 | 4.3 | 0% | 0 | 604 |
| Jul | 84 | 63 | 4.0 | 0% | 0 | 719 |
| Aug | 82 | 61 | 3.4 | 0% | 0 | 673 |
| Sep | 77 | 54 | 2.7 | 1% | 0 | 468 |
| Oct | 66 | 42 | 2.7 | 90% | 3 | 181 |
| Nov | 52 | 32 | 2.8 | 100% | 16 | 36 |
| Dec | 41 | 25 | 3.2 | 100% | 23 | 6 |
Monthly normals 1991–2020 at Washington Court House, OH (957 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.
Compared with the next station
The nearest other station, Hillsboro, OH, 14 miles southwest of Greenfield, has a last frost 1 day later (April 24), a first frost 1 day earlier (October 20), a season 3 days shorter.
When it snows in Greenfield, Ohio
The first measurable snow (0.1 inch or more) in Greenfield usually arrives around December 10, and the last of the season around March 13. Those are the middle dates across the winters of 1991–2020 at Washington Court House, OH, 13.3 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 41 days after the last snow.
Planting calendar for 45123
| When | What to do |
|---|---|
| February 12 – February 26 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 26 – March 12 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 26 – April 9 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 23 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 29 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 7 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 21 onward | Plant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter. |
The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.
Where these figures come from
ZIP 45123 is 13 miles from Washington Court House, OH, which stands at 957 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 4 other ZIP codes share the station; its figures are presented in full for 43160 (Washington Court House). The 2023 USDA Plant Hardiness Zone Map lists ZIP 45123 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°C) over 1991–2020; a zone describes winter lows, not frost dates.
Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.
Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.