USDA Hardiness Zone 5b
Frost Dates for 46341 — Hebron, Indiana
NOAA 1991–2020 normals from Lowell, IN (665 ft), 12 miles west.
Updated
In Hebron, the last spring frost (32°F) is around April 29 in half of years and has passed by May 14 in nine years out of ten. The first fall frost comes around October 16, as early as October 3 one year in ten, leaving a typical freeze-free season of 171 days (NOAA, Lowell, IN).
- Last spring frost
- April 29
- First fall frost
- October 16
- Growing season
- 171 days
- Hardiness zone
- 5b
50% probability
50% probability
freeze-free, 50%
-15 to -10°F (-26.1 to -23.3°C) coldest night
- First snow
- December 2
- Last snow
- March 17
- Winters with snow
- 100%
- Snow per year
- 29.7"
median, 1991–2020
median, 1991–2020
25 of 25 observed
NOAA normal
Frost risk by date in Hebron
Half of springs at Lowell, IN see their last 32°F night by April 29; 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 4 leaves a 30% risk of a frost on them, after May 8 20%, and after May 14 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 70% of the 125 Indiana stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 16 in half of years, as early as October 3 one year in ten, and holds off past October 28 one year in ten. A hard freeze of 28°F follows 10 days later, around October 26; in spring the one-in-ten date for 28°F is May 3, 11 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 190 days one year in ten and falls short of 149 one year in ten. On average 136 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 9 days longer, to about May 8, and return around October 6. Severe cold of 16°F or below comes every winter, usually between November 28 and March 14.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 25 | Apr 30 | May 2 | May 5 | May 8 | May 11 | May 15 | May 19 | May 25 |
| 32°F | Apr 14 | Apr 18 | Apr 22 | Apr 25 | Apr 29 | May 1 | May 4 | May 8 | May 14 |
| 28°F | Apr 1 | Apr 6 | Apr 9 | Apr 13 | Apr 16 | Apr 19 | Apr 23 | Apr 27 | May 3 |
| 24°F | Mar 19 | Mar 25 | Mar 28 | Mar 31 | Apr 2 | Apr 5 | Apr 9 | Apr 15 | Apr 21 |
| 20°F | Mar 7 | Mar 14 | Mar 18 | Mar 21 | Mar 24 | Mar 28 | Mar 31 | Apr 2 | Apr 7 |
| 16°F | Feb 27 | Mar 3 | Mar 7 | Mar 11 | Mar 14 | Mar 17 | Mar 20 | Mar 24 | Mar 30 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 23 | Sep 28 | Oct 1 | Oct 3 | Oct 6 | Oct 8 | Oct 10 | Oct 14 | Oct 18 |
| 32°F | Oct 3 | Oct 8 | Oct 11 | Oct 14 | Oct 16 | Oct 19 | Oct 21 | Oct 24 | Oct 28 |
| 28°F | Oct 13 | Oct 19 | Oct 22 | Oct 24 | Oct 26 | Oct 28 | Oct 31 | Nov 2 | Nov 8 |
| 24°F | Oct 24 | Oct 29 | Nov 1 | Nov 2 | Nov 5 | Nov 8 | Nov 11 | Nov 16 | Nov 22 |
| 20°F | Nov 2 | Nov 6 | Nov 10 | Nov 13 | Nov 17 | Nov 21 | Nov 25 | Nov 29 | Dec 4 |
| 16°F | Nov 10 | Nov 15 | Nov 20 | Nov 25 | Nov 28 | Dec 1 | Dec 4 | Dec 9 | Dec 16 |
Freeze probabilities 1991–2020 at Lowell, 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 46341 →Compare Hebron with another place →
Weather by month in Hebron
July is the warmest month at Lowell, IN, averaging 84°F by day and 63°F at night; January is the coldest at 32°F and 15°F. A freezing night is all but certain in every month from October 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 42% of years.
Warmth for growing adds up to 3,055 growing degree days a year (base 50°F), fewer than at 82% of the 125 Indiana stations. 35% of them (1,058) have built up by the end of June, and July adds the most, 713. Precipitation totals 39.8 inches a year, most in June (5.1") and least in February (1.9"); May to September bring 53% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 32 | 15 | 2.3 | 100% | 28 | 1 |
| Feb | 36 | 18 | 1.9 | 100% | 25 | 1 |
| Mar | 47 | 27 | 2.3 | 100% | 22 | 26 |
| Apr | 60 | 38 | 3.7 | 99% | 9 | 103 |
| May | 71 | 49 | 4.2 | 42% | 1 | 330 |
| Jun | 81 | 59 | 5.1 | 0% | 0 | 597 |
| Jul | 84 | 63 | 4.3 | 0% | 0 | 713 |
| Aug | 82 | 60 | 4.3 | 0% | 0 | 654 |
| Sep | 77 | 53 | 3.3 | 6% | <1 | 443 |
| Oct | 64 | 41 | 3.6 | 95% | 6 | 158 |
| Nov | 49 | 30 | 2.6 | 100% | 18 | 26 |
| Dec | 37 | 21 | 2.2 | 100% | 27 | 3 |
Monthly normals 1991–2020 at Lowell, IN (665 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, Wheatfield, IN, 12 miles southeast of Hebron, has a last frost 4 days earlier (April 25), a first frost 1 day later (October 17), a season 2 days longer.
When it snows in Hebron, Indiana
The first measurable snow (0.1 inch or more) in Hebron usually arrives around December 2, and the last of the season around March 17. Those are the middle dates across the winters of 1991–2020 at Lowell, IN, 11.6 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 43 days after the last snow.
Planting calendar for 46341
| When | What to do |
|---|---|
| February 18 – March 4 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 4 – March 18 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 1 – April 15 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 29 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 24 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 2 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 16 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 46341 is 12 miles from Lowell, IN, which stands at 665 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 5 other ZIP codes share the station; its figures are presented in full for 46307 (Crown Point). The 2023 USDA Plant Hardiness Zone Map lists ZIP 46341 in zone 5b, the band where the coldest night of the year averaged -15 to -10°F (-26.1 to -23.3°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.