USDA Hardiness Zone 7a
Frost Dates for 47112 — Corydon, Indiana
NOAA 1991–2020 normals from Brandenburg, KY (615 ft), 17 miles south.
Updated
In Corydon, the last spring frost (32°F) is around April 19 in half of years and has passed by May 2 in nine years out of ten. The first fall frost comes around October 24, as early as October 9 one year in ten, leaving a typical freeze-free season of 186 days (NOAA, Brandenburg, KY).
- Last spring frost
- April 19
- First fall frost
- October 24
- Growing season
- 186 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 Corydon
Half of springs at Brandenburg, KY see their last 32°F night by April 19; only one in ten is past it by April 4, and one in ten still has one after May 2. Planting tender crops after April 25 leaves a 30% risk of a frost on them, after April 29 20%, and after May 2 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 98% of the 125 Indiana stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 24 in half of years, as early as October 9 one year in ten, and holds off past November 4 one year in ten. A hard freeze of 28°F follows 9 days later, around November 2; in spring the one-in-ten date for 28°F is April 23, 9 days before the 32°F one. The freeze-free season lasts 186 days in a typical year, longer than at 62% of the 125 Indiana stations; it reaches 209 days one year in ten and falls short of 167 one year in ten. On average 109 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 April 29, and return around October 14. Severe cold of 16°F or below comes every winter, usually between December 6 and March 1.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 15 | Apr 19 | Apr 23 | Apr 26 | Apr 29 | May 1 | May 4 | May 7 | May 13 |
| 32°F | Apr 4 | Apr 9 | Apr 12 | Apr 16 | Apr 19 | Apr 22 | Apr 25 | Apr 29 | May 2 |
| 28°F | Mar 21 | Mar 27 | Mar 31 | Apr 3 | Apr 6 | Apr 9 | Apr 13 | Apr 17 | Apr 23 |
| 24°F | Mar 7 | Mar 15 | Mar 19 | Mar 23 | Mar 27 | Mar 30 | Apr 2 | Apr 5 | Apr 12 |
| 20°F | Feb 23 | Feb 28 | Mar 5 | Mar 9 | Mar 14 | Mar 18 | Mar 22 | Mar 27 | Apr 2 |
| 16°F | Feb 7 | Feb 14 | Feb 20 | Feb 26 | Mar 1 | Mar 5 | Mar 10 | Mar 15 | Mar 20 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 30 | Oct 5 | Oct 8 | Oct 11 | Oct 14 | Oct 16 | Oct 19 | Oct 22 | Oct 26 |
| 32°F | Oct 9 | Oct 15 | Oct 18 | Oct 21 | Oct 24 | Oct 26 | Oct 28 | Oct 31 | Nov 4 |
| 28°F | Oct 22 | Oct 26 | Oct 29 | Nov 1 | Nov 2 | Nov 5 | Nov 8 | Nov 12 | Nov 18 |
| 24°F | Nov 1 | Nov 3 | Nov 6 | Nov 10 | Nov 13 | Nov 16 | Nov 19 | Nov 23 | Nov 30 |
| 20°F | Nov 7 | Nov 13 | Nov 16 | Nov 20 | Nov 25 | Nov 29 | Dec 1 | Dec 6 | Dec 12 |
| 16°F | Nov 16 | Nov 24 | Nov 29 | Dec 2 | Dec 6 | Dec 11 | Dec 17 | Dec 24 | Dec 30 |
Freeze probabilities 1991–2020 at Brandenburg, 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 47112 →Compare Corydon with another place →
Frost risk through the year in Corydon
In Corydon, the spring curve drops under 10% on May 2 and the fall curve passes 10% on October 9, 160 days later; that gap is longer than at 70% of the 125 Indiana stations with frost dates. The spring risk falls from 90% to 10% over 28 days (April 4 to May 2) and the fall risk climbs from 10% to 90% over 26 days (October 9 to November 4): both ends of the season vary about as much. At Louisville Mcalpine, KY, 19 miles east, the same gap runs from April 14 to October 31, 40 days longer.
| Planted on | Another 32°F night | 28°F night |
|---|---|---|
| Apr 5 | 88% | 53% |
| Apr 12 | 70% | 33% |
| Apr 1950% date | 50% | 17% |
| Apr 26 | 28% | under 10% |
| May 3 | under 10% | under 10% |
| May 10 | under 10% | under 10% |
Weather by month in Corydon
July is the warmest month at Brandenburg, KY, averaging 86°F by day and 65°F at night; January is the coldest at 43°F and 23°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 15% of years.
Warmth for growing adds up to 3,851 growing degree days a year (base 50°F), more than at 78% of the 125 Indiana stations. 37% of them (1,436) have built up by the end of June, and July adds the most, 798. Precipitation totals 53.3 inches a year, most in May (6.0") and least in February (3.5"); May to September bring 43% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 43 | 23 | 4.0 | 100% | 25 | 11 |
| Feb | 47 | 25 | 3.5 | 100% | 22 | 19 |
| Mar | 57 | 33 | 4.9 | 100% | 16 | 68 |
| Apr | 69 | 42 | 5.4 | 93% | 5 | 224 |
| May | 76 | 53 | 6.0 | 15% | <1 | 452 |
| Jun | 83 | 61 | 4.5 | 0% | 0 | 663 |
| Jul | 86 | 65 | 4.9 | 0% | 0 | 798 |
| Aug | 86 | 63 | 3.6 | 0% | 0 | 763 |
| Sep | 80 | 56 | 3.8 | 2% | <1 | 542 |
| Oct | 69 | 44 | 3.9 | 80% | 3 | 241 |
| Nov | 56 | 34 | 4.0 | 100% | 15 | 58 |
| Dec | 46 | 27 | 4.8 | 100% | 23 | 13 |
Monthly normals 1991–2020 at Brandenburg, KY (615 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 Mcalpine, KY, 19 miles east of Corydon and 175 feet lower, has a last frost 19 days earlier (March 31), a first frost 16 days later (November 9), a season 39 days longer.
When it snows in Corydon, Indiana
The first measurable snow (0.1 inch or more) in Corydon 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, 21.3 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 42 days after the last snow.
Planting calendar for 47112
| When | What to do |
|---|---|
| February 8 – February 22 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 22 – March 8 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 22 – April 5 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 19 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 1 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 10 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 24 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 47112 is 17 miles from Brandenburg, KY, which stands at 615 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 5 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 47112 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.