Last frost date in Keene, NH

Average last frost
May 14

In Keene, the last spring frost comes around May 14 in an average year. Wait until May 28 if you want 90% odds of no more frost. The first fall frost usually arrives about October 1, which leaves 138 frost-free days. An early freeze before September 18 happens one year in ten.

Safe after (10% risk)
May 28
Average first frost
Oct 1
Frost-free season
138 days
Hard freeze (28°F) ends
May 2
Next 7 nights in Keene

Frost likely tonight, low 31°F

National Weather Service forecast, updated Oct 22, 12:57 UTC

  1. ThuOct 2231°frost
  2. FriOct 2326°hard freeze
  3. SatOct 2428°hard freeze
  4. SunOct 2532°frost
  5. MonOct 2639°
  6. TueOct 2734°possible frost
  7. WedOct 2836°possible frost
JanFebMarAprMayJunJulAugSepOctNovDecLast frost May 14First frost Oct 1138 frost-free daysBlue: chance of 32°F frost. Green: average frost-free season.JFMAMJJASOND138 frost-free days
Frost risk through the year at Keene, 1.4 miles from Keene.

Planting calendar for Keene

Windows count forward or back from the average frost dates above. Click a crop for dates across New Hampshire.

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost
Warm-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
TomatoesMay 21–Jun 4
PumpkinsMay 28–Jun 11
SunflowersMay 14–Jun 4
CucumbersMay 28–Jun 4
CornMay 21–Jun 4
Sweet potatoesJun 4–Jun 18
WatermelonMay 28–Jun 11
Green beansMay 21–Jun 11
ZucchiniMay 21–Jun 4
OkraJun 4–Jun 18
PeppersMay 28–Jun 11
BasilMay 21–Jun 4
Butternut squashMay 21–Jun 4
CantaloupeMay 28–Jun 11
EggplantMay 28–Jun 11
Cool-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
PotatoesApr 16–Apr 30
OnionsApr 2–Apr 23
CarrotsApr 23–May 28
LettuceApr 30–May 21
BroccoliApr 16–Apr 30
BeetsApr 16–May 28
PeasApr 2–Apr 16
CabbageApr 16–Apr 30
RadishesApr 9–May 21
Brussels sproutsApr 30–May 14
SpinachApr 2–Apr 23
CilantroApr 30–May 21
KaleApr 16–Apr 30
Collard greensApr 16–Apr 30
TurnipsApr 16–Apr 30
DillMay 14–May 28
CeleryMay 21–May 28
CauliflowerApr 30–May 14
LeeksApr 30–May 14
Swiss chardApr 30–May 28
ParsleyApr 30–May 21
Fall bulbs and garlic
JanFebMarAprMayJunJulAugSepOctNovDec
Tulip bulbsSep 17–Oct 22
GarlicSep 10–Oct 15
Daffodil bulbsSep 3–Oct 15
Perennials
JanFebMarAprMayJunJulAugSepOctNovDec
StrawberriesApr 16–Apr 30
AsparagusApr 16–Apr 30

Frost probabilities

ThresholdSpring, 90% chance laterSpring, 50%Spring, 10%Fall, 10% chance earlierFall, 50%Fall, 90%
Light frost, 32°FApr 30May 14May 28Sep 18Oct 1Oct 14
Hard freeze, 28°FApr 21May 2May 16Sep 29Oct 10Oct 25

Read the spring 10% column as the date after which only one year in ten still gets frost. That is the safer date for tomatoes, peppers and basil.

Where these numbers come from

NOAA station Keene (USC00274399) sits 1.4 miles from the center of Keene at 511 feet. Its averages cover 1991 to 2020. Low spots, valleys and open fields can keep getting frost a week or two after the station stops; city centers and lakeshores usually get less of it.

Questions

When is the last frost in Keene, NH?

The average last frost date in Keene is May 14, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after May 28.

When is the first frost in Keene?

The first frost in fall usually comes around October 1. One year in ten it arrives before September 18.

How long is the growing season in Keene?

About 138 days between the average last and first frost.

When should I plant tomatoes in Keene?

Plant tomato seedlings outside from May 21 to June 4. Start seeds indoors six to eight weeks earlier.

Nearby in New Hampshire

All 8 cities in New Hampshire