Last frost date in Bethany, OR

Average last frost
February 11

Expect the last frost in Bethany around February 11. Frost after March 5 happens in only one year out of ten. The first fall frost usually arrives about December 5, which leaves 303 frost-free days. An early freeze before November 11 happens one year in ten.

Safe after (10% risk)
Mar 5
Average first frost
Dec 5
Frost-free season
303 days
Hard freeze (28°F) ends
Jan 6
Next 6 nights in Bethany

No frost in the next 6 nights

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

  1. ThuOct 2241°
  2. FriOct 2339°
  3. SatOct 2442°
  4. SunOct 2544°
  5. MonOct 2642°
  6. TueOct 2742°
JanFebMarAprMayJunJulAugSepOctNovDecLast frost Feb 11First frost Dec 5303 frost-free daysBlue: chance of 32°F frost. Green: average frost-free season.JFMAMJJASOND303 frost-free days
Frost risk through the year at Nature Park-beaverton, 4.4 miles from Bethany.

Planting calendar for Bethany

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
TomatoesFeb 18–Mar 4
PumpkinsFeb 25–Mar 11
SunflowersFeb 15–Mar 8
CucumbersFeb 25–Mar 4
CornFeb 18–Mar 4
Sweet potatoesMar 4–Mar 18
WatermelonFeb 25–Mar 11
Green beansFeb 18–Mar 11
ZucchiniFeb 18–Mar 4
OkraMar 4–Mar 18
PeppersFeb 25–Mar 11
BasilFeb 18–Mar 4
Butternut squashFeb 18–Mar 4
CantaloupeFeb 25–Mar 11
EggplantFeb 25–Mar 11
Cool-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
PotatoesJan 14–Jan 28
OnionsDec 31–Jan 21
CarrotsJan 21–Feb 25
LettuceJan 28–Feb 18
BroccoliJan 14–Jan 28
BeetsJan 14–Feb 25
PeasDec 31–Jan 14
CabbageJan 14–Jan 28
RadishesJan 7–Feb 18
Brussels sproutsJan 28–Feb 11
SpinachDec 31–Jan 21
CilantroJan 28–Feb 18
KaleJan 14–Jan 28
Collard greensJan 14–Jan 28
TurnipsJan 14–Jan 28
DillFeb 11–Feb 25
CeleryFeb 18–Feb 25
CauliflowerJan 28–Feb 11
LeeksJan 28–Feb 11
Swiss chardJan 28–Feb 25
ParsleyJan 28–Feb 18
Fall bulbs and garlic
JanFebMarAprMayJunJulAugSepOctNovDec
Tulip bulbsDec 15–Jan 15
GarlicOct 15–Nov 30
Daffodil bulbsOct 15–Nov 30
Perennials
JanFebMarAprMayJunJulAugSepOctNovDec
StrawberriesJan 14–Jan 28
AsparagusJan 14–Jan 28

Frost probabilities

ThresholdSpring, 90% chance laterSpring, 50%Spring, 10%Fall, 10% chance earlierFall, 50%Fall, 90%
Light frost, 32°FDec 26Feb 11Mar 5Nov 11Dec 5Jan 12
Hard freeze, 28°FDec 2Jan 6Feb 16Nov 24Dec 21Feb 5

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 Nature Park-beaverton (USC00355945) sits 4.4 miles from the center of Bethany at 185 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 Bethany, OR?

The average last frost date in Bethany is February 11, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after March 5.

When is the first frost in Bethany?

The first frost in fall usually comes around December 5. One year in ten it arrives before November 11.

How long is the growing season in Bethany?

About 303 days between the average last and first frost.

When should I plant tomatoes in Bethany?

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

Nearby in Oregon

All 34 cities in Oregon