Last frost date in Seattle, WA
Expect the last frost in Seattle around March 8. Frost after March 29 happens in only one year out of ten. The first fall frost usually arrives about November 23, which leaves 259 frost-free days. An early freeze before November 4 happens one year in ten.
- Safe after (10% risk)
- Mar 29
- Average first frost
- Nov 23
- Frost-free season
- 259 days
- Hard freeze (28°F) ends
- Feb 11
No frost in the next 6 nights
National Weather Service forecast, updated Oct 22, 12:57 UTC
- ThuOct 2246°
- FriOct 2342°
- SatOct 2444°
- SunOct 2546°
- MonOct 2645°
- TueOct 2745°
Planting calendar for Seattle
Windows count forward or back from the average frost dates above. Click a crop for dates across Washington.
TomatoesMar 15–Mar 29
PumpkinsMar 22–Apr 5
SunflowersMar 8–Mar 29
CucumbersMar 22–Mar 29
CornMar 15–Mar 29
Sweet potatoesMar 29–Apr 12
WatermelonMar 22–Apr 5
Green beansMar 15–Apr 5
ZucchiniMar 15–Mar 29
OkraMar 29–Apr 12
PeppersMar 22–Apr 5
BasilMar 15–Mar 29
Butternut squashMar 15–Mar 29
CantaloupeMar 22–Apr 5
EggplantMar 22–Apr 5
PotatoesFeb 8–Feb 22
OnionsJan 25–Feb 15
CarrotsFeb 15–Mar 22
LettuceFeb 22–Mar 15
BroccoliFeb 8–Feb 22
BeetsFeb 8–Mar 22
PeasJan 25–Feb 8
CabbageFeb 8–Feb 22
RadishesFeb 1–Mar 15
Brussels sproutsFeb 22–Mar 8
SpinachJan 25–Feb 15
CilantroFeb 22–Mar 15
KaleFeb 8–Feb 22
Collard greensFeb 8–Feb 22
TurnipsFeb 8–Feb 22
DillMar 8–Mar 22
CeleryMar 15–Mar 22
CauliflowerFeb 22–Mar 8
LeeksFeb 22–Mar 8
Swiss chardFeb 22–Mar 22
ParsleyFeb 22–Mar 15
Tulip bulbsNov 9–Dec 14
GarlicOct 15–Nov 30
Daffodil bulbsOct 15–Nov 30
StrawberriesFeb 8–Feb 22
AsparagusFeb 8–Feb 22Frost probabilities
| Threshold | Spring, 90% chance later | Spring, 50% | Spring, 10% | Fall, 10% chance earlier | Fall, 50% | Fall, 90% |
|---|---|---|---|---|---|---|
| Light frost, 32°F | Feb 13 | Mar 8 | Mar 29 | Nov 4 | Nov 23 | Dec 16 |
| Hard freeze, 28°F | Dec 27 | Feb 11 | Mar 1 | Nov 17 | Dec 11 | Jan 17 |
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 Seattle Sand Pt Weather Office (USW00094290) sits 6.5 miles from the center of Seattle at 60 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 Seattle, WA?
The average last frost date in Seattle is March 8, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after March 29.
When is the first frost in Seattle?
The first frost in fall usually comes around November 23. One year in ten it arrives before November 4.
How long is the growing season in Seattle?
About 259 days between the average last and first frost.
When should I plant tomatoes in Seattle?
Plant tomato seedlings outside from March 15 to March 29. Start seeds indoors six to eight weeks earlier.
Nearby in Washington
- Mercer IslandMar 13
- Bainbridge IslandMar 29
- KirklandMar 8
- BellevueMar 8
- ShorelineMar 8
- BurienMar 2
- KenmoreMar 8
- TukwilaMar 2
- RedmondMar 8
- RentonMar 13
- Mountlake TerraceMar 8
- SeaTacMar 2