USDA Hardiness Zone 7a
Frost Dates for 42726 — Clarkson, Kentucky
NOAA 1991–2020 normals from Millerstown 4E, KY (600 ft), 9 miles east.
Updated
In Clarkson, the last spring frost (32°F) is around April 21 in half of years and has passed by May 6 in nine years out of ten. The first fall frost comes around October 18, as early as October 6 one year in ten, leaving a typical freeze-free season of 178 days (NOAA, Millerstown 4E, KY).
- Last spring frost
- April 21
- First fall frost
- October 18
- Growing season
- 178 days
- Hardiness zone
- 7a
50% probability
50% probability
freeze-free, 50%
0 to 5°F (-17.8 to -15.0°C) coldest night
- First snow
- December 24
- Last snow
- March 2
- Winters with snow
- 100%
- Snow per year
- 9.4"
median, 1991–2020
median, 1991–2020
19 of 19 observed
NOAA normal
Frost risk by date in Clarkson
Half of springs at Millerstown 4E, KY see their last 32°F night by April 21; only one in ten is past it by April 8, and one in ten still has one after May 6. Planting tender crops after April 28 leaves a 30% risk of a frost on them, after May 1 20%, and after May 6 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 85% of the 113 Kentucky stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 18 in half of years, as early as October 6 one year in ten, and holds off past October 28 one year in ten. A hard freeze of 28°F follows 8 days later, around October 26; in spring the one-in-ten date for 28°F is April 26, 10 days before the 32°F one. The freeze-free season lasts 178 days in a typical year, shorter than at 87% of the 113 Kentucky stations; it reaches 196 days one year in ten and falls short of 160 one year in ten. On average 113 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 10 days longer, to about May 1, and return around October 10. Severe cold of 16°F or below comes every winter, usually between December 1 and March 6.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 17 | Apr 22 | Apr 25 | Apr 29 | May 1 | May 3 | May 6 | May 9 | May 14 |
| 32°F | Apr 8 | Apr 12 | Apr 16 | Apr 19 | Apr 21 | Apr 24 | Apr 28 | May 1 | May 6 |
| 28°F | Mar 28 | Apr 1 | Apr 5 | Apr 7 | Apr 10 | Apr 13 | Apr 16 | Apr 20 | Apr 26 |
| 24°F | Mar 13 | Mar 19 | Mar 24 | Mar 28 | Mar 31 | Apr 2 | Apr 4 | Apr 8 | Apr 13 |
| 20°F | Feb 28 | Mar 6 | Mar 11 | Mar 15 | Mar 18 | Mar 22 | Mar 26 | Mar 30 | Apr 4 |
| 16°F | Feb 14 | Feb 22 | Feb 28 | Mar 3 | Mar 6 | Mar 11 | Mar 15 | Mar 19 | Mar 25 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 1 | Oct 4 | Oct 6 | Oct 8 | Oct 10 | Oct 12 | Oct 14 | Oct 17 | Oct 20 |
| 32°F | Oct 6 | Oct 11 | Oct 14 | Oct 16 | Oct 18 | Oct 20 | Oct 23 | Oct 24 | Oct 28 |
| 28°F | Oct 14 | Oct 19 | Oct 22 | Oct 24 | Oct 26 | Oct 29 | Oct 31 | Nov 2 | Nov 6 |
| 24°F | Oct 23 | Oct 28 | Oct 31 | Nov 2 | Nov 4 | Nov 7 | Nov 11 | Nov 15 | Nov 21 |
| 20°F | Nov 2 | Nov 5 | Nov 10 | Nov 13 | Nov 16 | Nov 20 | Nov 24 | Dec 1 | Dec 6 |
| 16°F | Nov 10 | Nov 16 | Nov 21 | Nov 26 | Dec 1 | Dec 3 | Dec 8 | Dec 14 | Dec 22 |
Freeze probabilities 1991–2020 at Millerstown 4E, KY, 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 42726 →Compare Clarkson with another place →
Compared with the next station
The nearest other station, Leitchfield 2 N, KY, 9 miles northwest of Clarkson, has a last frost 5 days later (April 26), a first frost 3 days earlier (October 15), a season 6 days shorter.
When it snows in Clarkson, Kentucky
The first measurable snow (0.1 inch or more) in Clarkson usually arrives around December 24, and the last of the season around March 2. Those are the middle dates across the winters of 1991–2020 at Leitchfield 2 N, KY, 8.9 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 50 days after the last snow.
Planting calendar for 42726
| When | What to do |
|---|---|
| February 10 – February 24 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 24 – March 10 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 24 – April 7 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 21 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 26 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 4 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 18 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 42726 is 9 miles from Millerstown 4E, KY, which stands at 600 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 42765 (Munfordville). The 2023 USDA Plant Hardiness Zone Map lists ZIP 42726 in zone 7a, the band where the coldest night of the year averaged 0 to 5°F (-17.8 to -15.0°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.