USDA Hardiness Zone 6a
Frost Dates for 46040 — Fortville, Indiana
NOAA 1991–2020 normals from Greenfield, IN (869 ft), 11 miles south.
Updated
In Fortville, the last spring frost (32°F) is around April 19 in half of years and has passed by May 7 in nine years out of ten. The first fall frost comes around October 22, as early as October 9 one year in ten, leaving a typical freeze-free season of 185 days (NOAA, Greenfield, IN).
- Last spring frost
- April 19
- First fall frost
- October 22
- Growing season
- 185 days
- Hardiness zone
- 6a
50% probability
50% probability
freeze-free, 50%
-10 to -5°F (-23.3 to -20.6°C) coldest night
- First snow
- December 5
- Last snow
- March 12
- Winters with snow
- 100%
- Snow per year
- 17.6"
median, 1991–2020
median, 1991–2020
19 of 19 observed
NOAA normal
Frost risk by date in Fortville
Half of springs at Greenfield, IN see their last 32°F night by April 19; only one in ten is past it by April 6, and one in ten still has one after May 7. Planting tender crops after April 26 leaves a 30% risk of a frost on them, after May 1 20%, and after May 7 10%. The 18 days between the even-odds date and the one-in-ten date is wider than at 84% of the 125 Indiana stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 22 in half of years, as early as October 9 one year in ten, and holds off past November 1 one year in ten. A hard freeze of 28°F follows 10 days later, around November 1; in spring the one-in-ten date for 28°F is April 23, 14 days before the 32°F one. The freeze-free season lasts 185 days in a typical year, longer than at 58% of the 125 Indiana stations; it reaches 203 days one year in ten and falls short of 164 one year in ten. On average 119 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 12 days longer, to about May 1, and return around October 12. Severe cold of 16°F or below comes every winter, usually between December 4 and March 8.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 16 | Apr 21 | Apr 24 | Apr 27 | May 1 | May 3 | May 7 | May 11 | May 16 |
| 32°F | Apr 6 | Apr 11 | Apr 13 | Apr 17 | Apr 19 | Apr 22 | Apr 26 | May 1 | May 7 |
| 28°F | Mar 24 | Mar 30 | Apr 2 | Apr 4 | Apr 7 | Apr 10 | Apr 13 | Apr 17 | Apr 23 |
| 24°F | Mar 12 | Mar 18 | Mar 22 | Mar 25 | Mar 29 | Mar 31 | Apr 2 | Apr 5 | Apr 10 |
| 20°F | Mar 1 | Mar 7 | Mar 11 | Mar 14 | Mar 18 | Mar 20 | Mar 24 | Mar 28 | Apr 1 |
| 16°F | Feb 16 | Feb 25 | Mar 1 | Mar 5 | Mar 8 | Mar 11 | Mar 15 | Mar 18 | Mar 23 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 30 | Oct 4 | Oct 7 | Oct 10 | Oct 12 | Oct 15 | Oct 17 | Oct 20 | Oct 24 |
| 32°F | Oct 9 | Oct 14 | Oct 17 | Oct 20 | Oct 22 | Oct 24 | Oct 26 | Oct 29 | Nov 1 |
| 28°F | Oct 21 | Oct 25 | Oct 28 | Oct 30 | Nov 1 | Nov 3 | Nov 6 | Nov 10 | Nov 16 |
| 24°F | Nov 1 | Nov 3 | Nov 6 | Nov 10 | Nov 13 | Nov 16 | Nov 20 | Nov 25 | Dec 1 |
| 20°F | Nov 8 | Nov 13 | Nov 17 | Nov 20 | Nov 24 | Nov 28 | Dec 1 | Dec 6 | Dec 14 |
| 16°F | Nov 16 | Nov 23 | Nov 27 | Dec 1 | Dec 4 | Dec 9 | Dec 13 | Dec 18 | Dec 23 |
Freeze probabilities 1991–2020 at Greenfield, IN, 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 46040 →Compare Fortville with another place →
Weather by month in Fortville
July is the warmest month at Greenfield, IN, averaging 84°F by day and 64°F at night; January is the coldest at 35°F and 19°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 21% of years.
Warmth for growing adds up to 3,388 growing degree days a year (base 50°F), more than at 52% of the 125 Indiana stations. 36% of them (1,219) have built up by the end of June, and July adds the most, 750. Precipitation totals 47.9 inches a year, most in June (5.7") and least in February (2.6"); May to September bring 48% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 35 | 19 | 3.3 | 100% | 27 | 3 |
| Feb | 39 | 22 | 2.6 | 100% | 24 | 4 |
| Mar | 50 | 30 | 3.7 | 100% | 20 | 38 |
| Apr | 62 | 41 | 4.7 | 95% | 5 | 146 |
| May | 73 | 52 | 5.3 | 21% | <1 | 391 |
| Jun | 81 | 61 | 5.7 | 0% | 0 | 636 |
| Jul | 84 | 64 | 4.8 | 0% | 0 | 750 |
| Aug | 83 | 62 | 3.7 | 0% | 0 | 704 |
| Sep | 78 | 55 | 3.7 | 1% | <1 | 488 |
| Oct | 65 | 43 | 3.5 | 85% | 4 | 187 |
| Nov | 51 | 33 | 3.7 | 100% | 15 | 36 |
| Dec | 39 | 24 | 3.2 | 100% | 24 | 5 |
Monthly normals 1991–2020 at Greenfield, IN (869 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, Carmel 3 E, IN, 12 miles west of Fortville, has a last frost 2 days later (April 21), a first frost 1 day earlier (October 21), a season 2 days shorter.
When it snows in Fortville, Indiana
The first measurable snow (0.1 inch or more) in Fortville usually arrives around December 5, and the last of the season around March 12. Those are the middle dates across the winters of 1991–2020 at Lapel 4 S, IN, 5.2 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 38 days after the last snow.
Planting calendar for 46040
| 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 July 30 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 8 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 22 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 46040 is 11 miles from Greenfield, IN, which stands at 869 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 46140 (Greenfield). The 2023 USDA Plant Hardiness Zone Map lists ZIP 46040 in zone 6a, the band where the coldest night of the year averaged -10 to -5°F (-23.3 to -20.6°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.