USDA Hardiness Zone 7a
Frost Dates for 40214 — Louisville, Kentucky
NOAA 1991–2020 normals from Louisville International Airport, KY (488 ft), 2 miles northeast.
Updated
In Louisville, the last spring frost (32°F) is around March 31 in half of years and has passed by April 16 in nine years out of ten. The first fall frost comes around November 7, as early as October 28 one year in ten, leaving a typical freeze-free season of 222 days (NOAA, Louisville International Airport, KY).
- Last spring frost
- March 31
- First fall frost
- November 7
- Growing season
- 222 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 7
- Last snow
- March 8
- Winters with snow
- 100%
- Snow per year
- 13.4"
median, 1991–2020
median, 1991–2020
30 of 30 observed
NOAA normal
Frost risk by date in Louisville
Half of springs at Louisville International Airport, KY see their last 32°F night by March 31; only one in ten is past it by March 14, and one in ten still has one after April 16. Planting tender crops after April 4 leaves a 30% risk of a frost on them, after April 9 20%, and after April 16 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 68% of the 113 Kentucky stations behind this site's ZIP pages.
In fall the first 32°F night comes by November 7 in half of years, as early as October 28 one year in ten, and holds off past November 23 one year in ten. A hard freeze of 28°F follows 10 days later, around November 17; in spring the one-in-ten date for 28°F is April 3, 13 days before the 32°F one. The freeze-free season lasts 222 days in a typical year, longer than at 98% of the 113 Kentucky stations; it reaches 243 days one year in ten and falls short of 202 one year in ten. On average 74 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 11 days longer, to about April 11, and return around October 29. Severe cold of 16°F or below comes in 99% of winters, usually between December 28 and February 12.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Mar 29 | Apr 2 | Apr 5 | Apr 8 | Apr 11 | Apr 14 | Apr 18 | Apr 22 | Apr 28 |
| 32°F | Mar 14 | Mar 20 | Mar 24 | Mar 28 | Mar 31 | Apr 1 | Apr 4 | Apr 9 | Apr 16 |
| 28°F | Mar 1 | Mar 8 | Mar 13 | Mar 16 | Mar 20 | Mar 23 | Mar 27 | Mar 30 | Apr 3 |
| 24°F | Feb 16 | Feb 25 | Mar 1 | Mar 6 | Mar 10 | Mar 13 | Mar 17 | Mar 21 | Mar 27 |
| 20°F | Feb 3 | Feb 9 | Feb 15 | Feb 22 | Feb 27 | Mar 2 | Mar 6 | Mar 11 | Mar 16 |
| 16°F99% of yrs | Jan 19 | Jan 29 | Feb 2 | Feb 6 | Feb 12 | Feb 18 | Feb 25 | Mar 1 | Mar 8 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 16 | Oct 21 | Oct 24 | Oct 26 | Oct 29 | Oct 31 | Nov 1 | Nov 4 | Nov 9 |
| 32°F | Oct 28 | Nov 1 | Nov 2 | Nov 4 | Nov 7 | Nov 10 | Nov 12 | Nov 17 | Nov 23 |
| 28°F | Nov 4 | Nov 8 | Nov 11 | Nov 14 | Nov 17 | Nov 21 | Nov 25 | Nov 30 | Dec 4 |
| 24°F | Nov 11 | Nov 16 | Nov 21 | Nov 26 | Dec 1 | Dec 3 | Dec 7 | Dec 13 | Dec 20 |
| 20°F | Nov 23 | Nov 30 | Dec 3 | Dec 8 | Dec 12 | Dec 19 | Dec 23 | Dec 27 | Jan 5 |
| 16°F99% of yrs | Dec 3 | Dec 12 | Dec 19 | Dec 25 | Dec 28 | Jan 1 | Jan 6 | Jan 11 | Jan 19 |
Freeze probabilities 1991–2020 at Louisville International Airport, 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 40214 →Compare Louisville with another place →
Weather by month in Louisville
July is the warmest month at Louisville International Airport, KY, averaging 89°F by day and 71°F at night; January is the coldest at 44°F and 28°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 42% of years.
Warmth for growing adds up to 4,759 growing degree days a year (base 50°F), more than at 96% of the 113 Kentucky stations. 38% of them (1,812) have built up by the end of June, and July adds the most, 927. Precipitation totals 48.4 inches a year, most in May (5.2") and least in January (3.4"); May to September bring 43% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 44 | 28 | 3.4 | 100% | 21 | 17 |
| Feb | 48 | 31 | 3.4 | 100% | 17 | 27 |
| Mar | 58 | 39 | 4.6 | 97% | 10 | 109 |
| Apr | 70 | 49 | 4.8 | 42% | 1 | 299 |
| May | 78 | 59 | 5.2 | 0% | 0 | 566 |
| Jun | 86 | 67 | 4.3 | 0% | 0 | 793 |
| Jul | 89 | 71 | 4.1 | 0% | 0 | 927 |
| Aug | 88 | 70 | 3.7 | 0% | 0 | 897 |
| Sep | 82 | 62 | 3.7 | 0% | 0 | 662 |
| Oct | 71 | 50 | 3.7 | 20% | 1 | 335 |
| Nov | 58 | 39 | 3.4 | 98% | 8 | 98 |
| Dec | 47 | 32 | 4.1 | 100% | 17 | 28 |
Monthly normals 1991–2020 at Louisville International Airport, KY (488 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, Louisville Bowman Field, KY, 8 miles northeast of Louisville, has a last frost 3 days later (April 3), a first frost 4 days earlier (November 3), a season 8 days shorter.
When it snows in Louisville, Kentucky
The first measurable snow (0.1 inch or more) in Louisville usually arrives around December 7, and the last of the season around March 8. Those are the middle dates across the winters of 1991–2020 at Louisville International Airport, KY, 2.4 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 23 days after the last snow.
Planting calendar for 40214
| When | What to do |
|---|---|
| January 20 – February 3 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 3 – February 17 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 3 – March 17 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| March 31 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 15 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 24 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 7 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 40214 is 2 miles from Louisville International Airport, KY, which stands at 488 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 9 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 40214 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.