USDA Hardiness Zone 6a
Frost Dates for 46975 — Rochester, Indiana
NOAA 1991–2020 normals from Rochester, IN (760 ft), 1 miles east.
Updated
In Rochester, the last spring frost (32°F) is around April 23 in half of years and has passed by May 9 in nine years out of ten. The first fall frost comes around October 21, as early as October 6 one year in ten, leaving a typical freeze-free season of 180 days (NOAA, Rochester, IN).
- Last spring frost
- April 23
- First fall frost
- October 21
- Growing season
- 180 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 11
- Winters with snow
- 100%
- Snow per year
- 30.1"
median, 1991–2020
median, 1991–2020
30 of 30 observed
NOAA normal
Frost risk by date in Rochester
Half of springs at Rochester, IN see their last 32°F night by April 23; only one in ten is past it by April 9, and one in ten still has one after May 9. Planting tender crops after April 29 leaves a 30% risk of a frost on them, after May 3 20%, and after May 9 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 35% of the 125 Indiana stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 21 in half of years, as early as October 6 one year in ten, and holds off past November 2 one year in ten. A hard freeze of 28°F follows 11 days later, around November 1; in spring the one-in-ten date for 28°F is April 26, 13 days before the 32°F one. The freeze-free season lasts 180 days in a typical year, shorter than at 54% of the 125 Indiana stations; it reaches 200 days one year in ten and falls short of 158 one year in ten. On average 128 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 3, and return around October 10. Severe cold of 16°F or below comes every winter, usually between December 5 and March 10.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 20 | Apr 24 | Apr 28 | Apr 30 | May 3 | May 7 | May 11 | May 15 | May 20 |
| 32°F | Apr 9 | Apr 14 | Apr 18 | Apr 20 | Apr 23 | Apr 26 | Apr 29 | May 3 | May 9 |
| 28°F | Mar 28 | Apr 2 | Apr 5 | Apr 7 | Apr 10 | Apr 14 | Apr 17 | Apr 21 | Apr 26 |
| 24°F | Mar 15 | Mar 21 | Mar 25 | Mar 30 | Apr 1 | Apr 3 | Apr 5 | Apr 9 | Apr 15 |
| 20°F | Mar 3 | Mar 9 | Mar 13 | Mar 17 | Mar 21 | Mar 24 | Mar 27 | Mar 31 | Apr 4 |
| 16°F | Feb 21 | Feb 28 | Mar 3 | Mar 6 | Mar 10 | Mar 13 | Mar 16 | Mar 21 | Mar 26 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 27 | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 12 | Oct 15 | Oct 18 | Oct 23 |
| 32°F | Oct 6 | Oct 12 | Oct 15 | Oct 18 | Oct 21 | Oct 23 | Oct 26 | Oct 29 | Nov 2 |
| 28°F | Oct 19 | Oct 24 | Oct 27 | Oct 31 | Nov 1 | Nov 3 | Nov 6 | Nov 10 | Nov 17 |
| 24°F | Nov 1 | Nov 3 | Nov 6 | Nov 8 | Nov 12 | Nov 17 | Nov 22 | Nov 26 | Dec 2 |
| 20°F | Nov 7 | Nov 11 | Nov 17 | Nov 21 | Nov 25 | Nov 29 | Dec 2 | Dec 7 | Dec 15 |
| 16°F | Nov 17 | Nov 24 | Nov 28 | Dec 1 | Dec 5 | Dec 8 | Dec 13 | Dec 18 | Dec 24 |
Freeze probabilities 1991–2020 at Rochester, 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 46975 →Compare Rochester with another place →
Weather by month in Rochester
July is the warmest month at Rochester, IN, averaging 83°F by day and 63°F at night; January is the coldest at 32°F and 17°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 25% of years.
Warmth for growing adds up to 3,097 growing degree days a year (base 50°F), fewer than at 74% of the 125 Indiana stations. 35% of them (1,083) have built up by the end of June, and July adds the most, 713. Precipitation totals 40.7 inches a year, most in May (4.4") and least in February (2.3"); May to September bring 50% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 32 | 17 | 2.8 | 100% | 28 | 1 |
| Feb | 36 | 20 | 2.3 | 100% | 25 | 2 |
| Mar | 47 | 28 | 2.6 | 100% | 21 | 27 |
| Apr | 60 | 39 | 3.9 | 98% | 8 | 109 |
| May | 71 | 50 | 4.4 | 25% | <1 | 343 |
| Jun | 80 | 60 | 4.3 | 0% | 0 | 602 |
| Jul | 83 | 63 | 4.4 | 0% | 0 | 713 |
| Aug | 82 | 61 | 4.1 | 0% | 0 | 659 |
| Sep | 76 | 53 | 3.2 | 4% | <1 | 443 |
| Oct | 64 | 43 | 3.2 | 85% | 4 | 167 |
| Nov | 49 | 32 | 3.1 | 100% | 16 | 30 |
| Dec | 37 | 23 | 2.4 | 100% | 26 | 3 |
Monthly normals 1991–2020 at Rochester, IN (760 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, Winamac 2SSE, IN, 19 miles west of Rochester, has a last frost 2 days later (April 25), a first frost 3 days earlier (October 18), a season 7 days shorter.
When it snows in Rochester, Indiana
The first measurable snow (0.1 inch or more) in Rochester usually arrives around December 5, and the last of the season around March 11. Those are the middle dates across the winters of 1991–2020 at Rochester, IN, 1.4 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 46975
| When | What to do |
|---|---|
| February 12 – February 26 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 26 – March 12 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 26 – April 9 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 23 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 29 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 7 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 21 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 46975 is 1 mile from Rochester, IN, which stands at 760 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 46975 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.