USDA Hardiness Zone 6a
Frost Dates for 46797 — Woodburn, Indiana
NOAA 1991–2020 normals from Woodburn 3N, IN (710 ft), 3 miles northeast.
Updated
In Woodburn, the last spring frost (32°F) is around April 27 in half of years and has passed by May 11 in nine years out of ten. The first fall frost comes around October 19, as early as October 4 one year in ten, leaving a typical freeze-free season of 174 days (NOAA, Woodburn 3N, IN).
- Last spring frost
- April 27
- First fall frost
- October 19
- Growing season
- 174 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
- November 30
- Last snow
- March 21
- Winters with snow
- 90%
- Snow per year
- 23.6"
median, 1991–2020
median, 1991–2020
26 of 29 observed
NOAA normal
Frost risk by date in Woodburn
Half of springs at Woodburn 3N, IN see their last 32°F night by April 27; only one in ten is past it by April 13, and one in ten still has one after May 11. Planting tender crops after May 3 leaves a 30% risk of a frost on them, after May 6 20%, and after May 11 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 89% of the 125 Indiana stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 19 in half of years, as early as October 4 one year in ten, and holds off past October 31 one year in ten. A hard freeze of 28°F follows 11 days later, around October 30; in spring the one-in-ten date for 28°F is May 1, 10 days before the 32°F one. The freeze-free season lasts 174 days in a typical year, shorter than at 72% of the 125 Indiana stations; it reaches 194 days one year in ten and falls short of 153 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 8 days longer, to about May 5, and return around October 7. Severe cold of 16°F or below comes every winter, usually between December 1 and March 14.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 23 | Apr 27 | Apr 30 | May 3 | May 5 | May 8 | May 11 | May 15 | May 20 |
| 32°F | Apr 13 | Apr 17 | Apr 21 | Apr 24 | Apr 27 | Apr 30 | May 3 | May 6 | May 11 |
| 28°F | Mar 31 | Apr 4 | Apr 8 | Apr 12 | Apr 15 | Apr 17 | Apr 20 | Apr 25 | May 1 |
| 24°F | Mar 20 | Mar 24 | Mar 28 | Mar 31 | Apr 2 | Apr 5 | Apr 8 | Apr 12 | Apr 17 |
| 20°F | Mar 7 | Mar 14 | Mar 18 | Mar 21 | Mar 24 | Mar 28 | Mar 31 | Apr 3 | Apr 7 |
| 16°F | Feb 24 | Mar 2 | Mar 6 | Mar 11 | Mar 14 | Mar 18 | Mar 22 | Mar 26 | Mar 30 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 23 | Sep 28 | Oct 1 | Oct 4 | Oct 7 | Oct 9 | Oct 12 | Oct 15 | Oct 21 |
| 32°F | Oct 4 | Oct 9 | Oct 13 | Oct 15 | Oct 19 | Oct 21 | Oct 24 | Oct 27 | Oct 31 |
| 28°F | Oct 16 | Oct 21 | Oct 24 | Oct 27 | Oct 30 | Nov 1 | Nov 4 | Nov 6 | Nov 12 |
| 24°F | Oct 29 | Nov 1 | Nov 4 | Nov 6 | Nov 9 | Nov 13 | Nov 16 | Nov 20 | Nov 25 |
| 20°F | Nov 6 | Nov 10 | Nov 14 | Nov 18 | Nov 21 | Nov 25 | Nov 28 | Dec 2 | Dec 10 |
| 16°F | Nov 12 | Nov 19 | Nov 24 | Nov 28 | Dec 1 | Dec 5 | Dec 10 | Dec 16 | Dec 22 |
Freeze probabilities 1991–2020 at Woodburn 3N, 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 46797 →Compare Woodburn with another place →
Weather by month in Woodburn
July is the warmest month at Woodburn 3N, IN, averaging 84°F by day and 62°F at night; January is the coldest at 32°F and 18°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 3,005 growing degree days a year (base 50°F), fewer than at 91% of the 125 Indiana stations. 34% of them (1,031) have built up by the end of June, and July adds the most, 722.
| Month | High °F | Low °F | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|
| Jan | 32 | 18 | 100% | 29 | 1 |
| Feb | 35 | 19 | 100% | 26 | 1 |
| Mar | 46 | 27 | 100% | 22 | 22 |
| Apr | 60 | 37 | 99% | 9 | 90 |
| May | 71 | 49 | 38% | <1 | 323 |
| Jun | 81 | 59 | 0% | 0 | 595 |
| Jul | 84 | 62 | 0% | 0 | 722 |
| Aug | 82 | 60 | 0% | 0 | 648 |
| Sep | 76 | 52 | 6% | <1 | 427 |
| Oct | 63 | 42 | 89% | 4 | 153 |
| Nov | 49 | 31 | 100% | 18 | 21 |
| Dec | 37 | 23 | 100% | 26 | 3 |
Monthly normals 1991–2020 at Woodburn 3N, IN (710 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, Hicksville, OH, 12 miles northeast of Woodburn, has a last frost 1 day later (April 28), a first frost 2 days earlier (October 17), a season 4 days shorter.
When it snows in Woodburn, Indiana
The first measurable snow (0.1 inch or more) in Woodburn usually arrives around November 30, and the last of the season around March 21. Those are the middle dates across the winters of 1991–2020 at Paulding, OH, 14.5 miles away: half of years saw snow earlier, half later. Snow fell in 90% of those winters. The last 32°F night of spring typically comes 37 days after the last snow.
Planting calendar for 46797
| 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 27 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 5 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 19 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 46797 is 3 miles from Woodburn 3N, IN, which stands at 710 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 6 other ZIP codes share the station; its figures are presented in full for 46835 (Fort Wayne). The 2023 USDA Plant Hardiness Zone Map lists ZIP 46797 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.