Last frost date in Portland, OR

Average last frost
February 25

The average last frost in Portland is February 25. By March 21 the chance of another 32°F night drops to 1 in 10. The first fall frost usually arrives about December 1, which leaves 280 frost-free days. An early freeze before November 10 happens one year in ten.

Safe after (10% risk)
Mar 21
Average first frost
Dec 1
Frost-free season
280 days
Hard freeze (28°F) ends
Jan 31
Next 6 nights in Portland

No frost in the next 6 nights

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

  1. ThuOct 2242°
  2. FriOct 2339°
  3. SatOct 2443°
  4. SunOct 2545°
  5. MonOct 2643°
  6. TueOct 2742°
JanFebMarAprMayJunJulAugSepOctNovDecLast frost Feb 25First frost Dec 1280 frost-free daysBlue: chance of 32°F frost. Green: average frost-free season.JFMAMJJASOND280 frost-free days
Frost risk through the year at Portland Kgw-tv, 2.3 miles from Portland.

Planting calendar for Portland

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

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost
Warm-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
TomatoesMar 4–Mar 18
PumpkinsMar 11–Mar 25
SunflowersFeb 25–Mar 18
CucumbersMar 11–Mar 18
CornMar 4–Mar 18
Sweet potatoesMar 18–Apr 1
WatermelonMar 11–Mar 25
Green beansMar 4–Mar 25
ZucchiniMar 4–Mar 18
OkraMar 18–Apr 1
PeppersMar 11–Mar 25
BasilMar 4–Mar 18
Butternut squashMar 4–Mar 18
CantaloupeMar 11–Mar 25
EggplantMar 11–Mar 25
Cool-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
PotatoesJan 28–Feb 11
OnionsJan 14–Feb 4
CarrotsFeb 4–Mar 11
LettuceFeb 11–Mar 4
BroccoliJan 28–Feb 11
BeetsJan 28–Mar 11
PeasJan 14–Jan 28
CabbageJan 28–Feb 11
RadishesJan 21–Mar 4
Brussels sproutsFeb 11–Feb 25
SpinachJan 14–Feb 4
CilantroFeb 11–Mar 4
KaleJan 28–Feb 11
Collard greensJan 28–Feb 11
TurnipsJan 28–Feb 11
DillFeb 25–Mar 11
CeleryMar 4–Mar 11
CauliflowerFeb 11–Feb 25
LeeksFeb 11–Feb 25
Swiss chardFeb 11–Mar 11
ParsleyFeb 11–Mar 4
Fall bulbs and garlic
JanFebMarAprMayJunJulAugSepOctNovDec
Tulip bulbsNov 17–Dec 15
GarlicOct 15–Nov 30
Daffodil bulbsOct 15–Nov 30
Perennials
JanFebMarAprMayJunJulAugSepOctNovDec
StrawberriesJan 28–Feb 11
AsparagusJan 28–Feb 11

Frost probabilities

ThresholdSpring, 90% chance laterSpring, 50%Spring, 10%Fall, 10% chance earlierFall, 50%Fall, 90%
Light frost, 32°FJan 24Feb 25Mar 21Nov 10Dec 1Dec 27
Hard freeze, 28°FDec 21Jan 31Feb 26Nov 25Dec 20Jan 30

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 Portland Kgw-tv (USC00356749) sits 2.3 miles from the center of Portland at 159 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 Portland, OR?

The average last frost date in Portland is February 25, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after March 21.

When is the first frost in Portland?

The first frost in fall usually comes around December 1. One year in ten it arrives before November 10.

How long is the growing season in Portland?

About 280 days between the average last and first frost.

When should I plant tomatoes in Portland?

Plant tomato seedlings outside from March 4 to March 18. Start seeds indoors six to eight weeks earlier.

Nearby in Oregon

All 34 cities in Oregon