USDA Hardiness Zone 6a
Frost Dates for 46151 — Martinsville, Indiana
NOAA 1991–2020 normals from Martinsville 2 SW, IN (592 ft), 3 miles southwest.
Updated
In Martinsville, the last spring frost (32°F) is around April 24 in half of years and has passed by May 11 in nine years out of ten. The first fall frost comes around October 15, as early as October 2 one year in ten, leaving a typical freeze-free season of 173 days (NOAA, Martinsville 2 SW, IN).
- Last spring frost
- April 24
- First fall frost
- October 15
- Growing season
- 173 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 9
- Last snow
- March 6
- Winters with snow
- 100%
- Snow per year
- 16.7"
median, 1991–2020
median, 1991–2020
28 of 28 observed
NOAA normal
Frost risk by date in Martinsville
Half of springs at Martinsville 2 SW, IN see their last 32°F night by April 24; only one in ten is past it by April 10, and one in ten still has one after May 11. Planting tender crops after May 1 leaves a 30% risk of a frost on them, after May 5 20%, and after May 11 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 15 in half of years, as early as October 2 one year in ten, and holds off past October 29 one year in ten. A hard freeze of 28°F follows 11 days later, around October 26; in spring the one-in-ten date for 28°F is April 30, 11 days before the 32°F one. The freeze-free season lasts 173 days in a typical year, shorter than at 77% of the 125 Indiana stations; it reaches 191 days one year in ten and falls short of 152 one year in ten. On average 127 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 4, and return around October 6. Severe cold of 16°F or below comes every winter, usually between December 1 and March 9.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 20 | Apr 24 | Apr 28 | May 1 | May 4 | May 7 | May 11 | May 15 | May 21 |
| 32°F | Apr 10 | Apr 14 | Apr 17 | Apr 21 | Apr 24 | Apr 28 | May 1 | May 5 | May 11 |
| 28°F | Mar 29 | Apr 3 | Apr 6 | Apr 8 | Apr 12 | Apr 15 | Apr 19 | Apr 23 | Apr 30 |
| 24°F | Mar 14 | Mar 21 | Mar 25 | Mar 29 | Mar 31 | Apr 2 | Apr 4 | Apr 8 | Apr 14 |
| 20°F | Feb 28 | Mar 8 | Mar 12 | Mar 16 | Mar 19 | Mar 22 | Mar 26 | Mar 30 | Apr 3 |
| 16°F | Feb 16 | Feb 25 | Mar 2 | Mar 6 | Mar 9 | Mar 13 | Mar 16 | Mar 20 | Mar 25 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 24 | Sep 29 | Oct 1 | Oct 4 | Oct 6 | Oct 8 | Oct 11 | Oct 14 | Oct 19 |
| 32°F | Oct 2 | Oct 7 | Oct 10 | Oct 13 | Oct 15 | Oct 18 | Oct 21 | Oct 24 | Oct 29 |
| 28°F | Oct 12 | Oct 17 | Oct 21 | Oct 23 | Oct 26 | Oct 28 | Oct 31 | Nov 2 | Nov 7 |
| 24°F | Oct 23 | Oct 27 | Oct 30 | Nov 1 | Nov 5 | Nov 7 | Nov 11 | Nov 15 | Nov 24 |
| 20°F | Nov 1 | Nov 6 | Nov 10 | Nov 14 | Nov 18 | Nov 23 | Nov 27 | Dec 2 | Dec 8 |
| 16°F | Nov 13 | Nov 20 | Nov 25 | Nov 28 | Dec 1 | Dec 5 | Dec 11 | Dec 17 | Dec 23 |
Freeze probabilities 1991–2020 at Martinsville 2 SW, 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 46151 →Compare Martinsville with another place →
Frost risk through the year in Martinsville
In Martinsville, the spring curve drops under 10% on May 11 and the fall curve passes 10% on October 2, 144 days later; that gap is shorter than at 78% of the 125 Indiana stations with frost dates. The spring risk falls from 90% to 10% over 31 days (April 10 to May 11) and the fall risk climbs from 10% to 90% over 27 days (October 2 to October 29): both ends of the season vary about as much. At Bloomington Indiana Univ, IN, 19 miles south, the same gap runs from May 3 to October 11, 17 days longer.
| Planted on | Another 32°F night | 28°F night |
|---|---|---|
| Apr 10 | over 90% | 55% |
| Apr 17 | 70% | 35% |
| Apr 2450% date | 50% | 19% |
| May 1 | 30% | under 10% |
| May 8 | 15% | under 10% |
| May 15 | under 10% | under 10% |
Weather by month in Martinsville
July is the warmest month at Martinsville 2 SW, IN, averaging 84°F by day and 63°F at night; January is the coldest at 36°F and 19°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 31% of years.
Warmth for growing adds up to 3,244 growing degree days a year (base 50°F), fewer than at 60% of the 125 Indiana stations. 36% of them (1,165) have built up by the end of June, and July adds the most, 722. Precipitation totals 45.5 inches a year, most in June (5.3") and least in February (2.4"); May to September bring 47% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 36 | 19 | 3.2 | 100% | 27 | 4 |
| Feb | 41 | 21 | 2.4 | 100% | 24 | 5 |
| Mar | 51 | 29 | 3.6 | 100% | 20 | 39 |
| Apr | 63 | 40 | 4.8 | 98% | 7 | 142 |
| May | 73 | 50 | 5.0 | 31% | 1 | 370 |
| Jun | 81 | 60 | 5.3 | 0% | 0 | 606 |
| Jul | 84 | 63 | 4.1 | 0% | 0 | 722 |
| Aug | 83 | 61 | 3.4 | 0% | 0 | 679 |
| Sep | 78 | 53 | 3.5 | 6% | <1 | 462 |
| Oct | 66 | 41 | 3.5 | 94% | 6 | 171 |
| Nov | 52 | 32 | 3.6 | 100% | 17 | 38 |
| Dec | 41 | 24 | 3.1 | 100% | 24 | 7 |
Monthly normals 1991–2020 at Martinsville 2 SW, IN (592 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, Bloomington Indiana Univ, IN, 19 miles south of Martinsville and 238 feet higher, has a last frost 9 days earlier (April 15), a first frost 11 days later (October 26), a season 19 days longer.
When it snows in Martinsville, Indiana
The first measurable snow (0.1 inch or more) in Martinsville usually arrives around December 9, and the last of the season around March 6. Those are the middle dates across the winters of 1991–2020 at Martinsville 2 SW, IN, 3.4 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 49 days after the last snow.
Planting calendar for 46151
| When | What to do |
|---|---|
| February 13 – February 27 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 27 – March 13 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 27 – April 10 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 24 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 23 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 1 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 15 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 46151 is 3 miles from Martinsville 2 SW, IN, which stands at 592 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 46151 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.