Last frost date in Missoula, MT

Average last frost
May 10

In Missoula, the last spring frost comes around May 10 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 143 frost-free days. An early freeze before September 16 happens one year in ten.

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

Frost likely Fri night, low 30°F

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

  1. ThuOct 2240°
  2. FriOct 2330°frost
  3. SatOct 2427°hard freeze
  4. SunOct 2526°hard freeze
  5. MonOct 2627°hard freeze
  6. TueOct 2727°hard freeze
  7. WedOct 2826°hard freeze
JanFebMarAprMayJunJulAugSepOctNovDecLast frost May 10First frost Oct 1143 frost-free daysBlue: chance of 32°F frost. Green: average frost-free season.JFMAMJJASOND143 frost-free days
Frost risk through the year at Missoula 2 NE, 3.2 miles from Missoula.

Planting calendar for Missoula

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

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost
Warm-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
TomatoesMay 17–May 31
PumpkinsMay 24–Jun 7
SunflowersMay 10–May 31
CucumbersMay 24–May 31
CornMay 17–May 31
Sweet potatoesMay 31–Jun 14
WatermelonMay 24–Jun 7
Green beansMay 17–Jun 7
ZucchiniMay 17–May 31
OkraMay 31–Jun 14
PeppersMay 24–Jun 7
BasilMay 17–May 31
Butternut squashMay 17–May 31
CantaloupeMay 24–Jun 7
EggplantMay 24–Jun 7
Cool-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
PotatoesApr 12–Apr 26
OnionsMar 29–Apr 19
CarrotsApr 19–May 24
LettuceApr 26–May 17
BroccoliApr 12–Apr 26
BeetsApr 12–May 24
PeasMar 29–Apr 12
CabbageApr 12–Apr 26
RadishesApr 5–May 17
Brussels sproutsApr 26–May 10
SpinachMar 29–Apr 19
CilantroApr 26–May 17
KaleApr 12–Apr 26
Collard greensApr 12–Apr 26
TurnipsApr 12–Apr 26
DillMay 10–May 24
CeleryMay 17–May 24
CauliflowerApr 26–May 10
LeeksApr 26–May 10
Swiss chardApr 26–May 24
ParsleyApr 26–May 17
Fall bulbs and garlic
JanFebMarAprMayJunJulAugSepOctNovDec
Tulip bulbsSep 17–Oct 22
GarlicSep 10–Oct 15
Daffodil bulbsSep 3–Oct 15
Perennials
JanFebMarAprMayJunJulAugSepOctNovDec
StrawberriesApr 12–Apr 26
AsparagusApr 12–Apr 26

Frost probabilities

ThresholdSpring, 90% chance laterSpring, 50%Spring, 10%Fall, 10% chance earlierFall, 50%Fall, 90%
Light frost, 32°FApr 27May 10May 28Sep 16Oct 1Oct 15
Hard freeze, 28°FApr 12Apr 28May 11Sep 28Oct 12Oct 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 Missoula 2 NE (USC00245735) sits 3.2 miles from the center of Missoula at 3,420 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 Missoula, MT?

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

When is the first frost in Missoula?

The first frost in fall usually comes around October 1. One year in ten it arrives before September 16.

How long is the growing season in Missoula?

About 143 days between the average last and first frost.

When should I plant tomatoes in Missoula?

Plant tomato seedlings outside from May 17 to May 31. Start seeds indoors six to eight weeks earlier.

Nearby in Montana

All 7 cities in Montana