USDA Hardiness Zone 6a
Frost Dates for 46787 — South Whitley, Indiana
NOAA 1991–2020 normals from Columbia City, IN (834 ft), 9 miles northeast.
Updated
In South Whitley, the last spring frost (32°F) is around April 27 in half of years and has passed by May 14 in nine years out of ten. The first fall frost comes around October 17, as early as October 1 one year in ten, leaving a typical freeze-free season of 171 days (NOAA, Columbia City, IN).
- Last spring frost
- April 27
- First fall frost
- October 17
- Growing season
- 171 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 18
- Winters with snow
- 100%
- Snow per year
- 21.4"
median, 1991–2020
median, 1991–2020
30 of 30 observed
NOAA normal
Frost risk by date in South Whitley
Half of springs at Columbia City, IN see their last 32°F night by April 27; only one in ten is past it by April 14, and one in ten still has one after May 14. Planting tender crops after May 3 leaves a 30% risk of a frost on them, after May 7 20%, and after May 14 10%. The 17 days between the even-odds date and the one-in-ten date is wider than at 66% of the 125 Indiana stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 17 in half of years, as early as October 1 one year in ten, and holds off past November 1 one year in ten. A hard freeze of 28°F follows 12 days later, around October 29; in spring the one-in-ten date for 28°F is May 2, 12 days before the 32°F one. The freeze-free season lasts 171 days in a typical year, shorter than at 84% of the 125 Indiana stations; it reaches 193 days one year in ten and falls short of 149 one year in ten. On average 134 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 7, and return around October 5. Severe cold of 16°F or below comes every winter, usually between December 1 and March 17.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 23 | Apr 28 | May 1 | May 4 | May 7 | May 10 | May 13 | May 16 | May 23 |
| 32°F | Apr 14 | Apr 18 | Apr 21 | Apr 24 | Apr 27 | Apr 30 | May 3 | May 7 | May 14 |
| 28°F | Apr 3 | Apr 7 | Apr 11 | Apr 14 | Apr 16 | Apr 19 | Apr 22 | Apr 26 | May 2 |
| 24°F | Mar 21 | Mar 28 | Apr 1 | Apr 3 | Apr 6 | Apr 8 | Apr 12 | Apr 16 | Apr 20 |
| 20°F | Mar 10 | Mar 16 | Mar 20 | Mar 24 | Mar 27 | Mar 30 | Apr 2 | Apr 5 | Apr 11 |
| 16°F | Mar 1 | Mar 6 | Mar 10 | Mar 13 | Mar 17 | Mar 21 | Mar 24 | Mar 29 | Apr 1 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 22 | Sep 27 | Sep 30 | Oct 2 | Oct 5 | Oct 8 | Oct 11 | Oct 14 | Oct 20 |
| 32°F | Oct 1 | Oct 7 | Oct 11 | Oct 14 | Oct 17 | Oct 20 | Oct 23 | Oct 27 | Nov 1 |
| 28°F | Oct 14 | Oct 20 | Oct 23 | Oct 26 | Oct 29 | Nov 1 | Nov 2 | Nov 5 | Nov 11 |
| 24°F | Oct 28 | Nov 1 | Nov 3 | Nov 5 | Nov 8 | Nov 12 | Nov 15 | Nov 19 | Nov 26 |
| 20°F | Nov 5 | Nov 9 | Nov 14 | Nov 17 | Nov 19 | Nov 23 | Nov 28 | Dec 2 | Dec 9 |
| 16°F | Nov 12 | Nov 18 | Nov 22 | Nov 27 | Dec 1 | Dec 4 | Dec 8 | Dec 14 | Dec 21 |
Freeze probabilities 1991–2020 at Columbia City, 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 46787 →Compare South Whitley with another place →
Weather by month in South Whitley
July is the warmest month at Columbia City, IN, averaging 83°F by day and 62°F at night; January is the coldest at 32°F and 16°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 38% of years.
Warmth for growing adds up to 2,939 growing degree days a year (base 50°F), fewer than at 94% of the 125 Indiana stations. 35% of them (1,017) have built up by the end of June, and July adds the most, 691. Precipitation totals 39.1 inches a year, most in June (4.6") and least in February (2.0"); May to September bring 51% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 32 | 16 | 2.5 | 100% | 28 | 1 |
| Feb | 35 | 19 | 2.0 | 100% | 25 | 1 |
| Mar | 46 | 27 | 2.6 | 100% | 22 | 23 |
| Apr | 59 | 38 | 3.8 | 99% | 9 | 99 |
| May | 70 | 49 | 4.3 | 38% | 1 | 320 |
| Jun | 79 | 59 | 4.6 | 0% | 0 | 573 |
| Jul | 83 | 62 | 3.9 | 0% | 0 | 691 |
| Aug | 81 | 60 | 4.1 | 0% | 0 | 634 |
| Sep | 75 | 53 | 3.0 | 9% | <1 | 420 |
| Oct | 63 | 42 | 2.9 | 89% | 5 | 151 |
| Nov | 49 | 31 | 3.0 | 100% | 17 | 24 |
| Dec | 37 | 22 | 2.4 | 100% | 26 | 3 |
Monthly normals 1991–2020 at Columbia City, IN (834 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, N Manchester Wwtp, IN, 10 miles southwest of South Whitley, has a last frost 1 day earlier (April 26), a first frost 2 days later (October 19), a season 3 days longer.
When it snows in South Whitley, Indiana
The first measurable snow (0.1 inch or more) in South Whitley usually arrives around December 5, and the last of the season around March 18. Those are the middle dates across the winters of 1991–2020 at Columbia City, IN, 8.5 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 40 days after the last snow.
Planting calendar for 46787
| When | What to do |
|---|---|
| February 16 – March 2 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 2 – March 16 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 30 – April 13 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 27 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 25 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 3 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 17 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 46787 is 9 miles from Columbia City, IN, which stands at 834 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 46725 (Columbia City). The 2023 USDA Plant Hardiness Zone Map lists ZIP 46787 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.