ZIP 98121 Zone 9a
Washington · USDA zone 9a, average annual extreme minimum 20°F to 25°F.
Nearest qualified station: SEATTLE BOEING FLD, WA US (USW00024234), 6.3 miles from the Census ZCTA internal point for this ZIP.
Outside the median season Growing seasonTicks: 10%, 50%, and 90%
Last 32°F in spring
NCEI’s probability is the chance the last spring minimum of 32°F or lower occurs on or after the date.
| Probability | Date | How to read it |
|---|---|---|
| 90% | February 20 | Earlier date. A last 32°F on or after this day is common. |
| 50% | March 13 | Median. |
| 10% | April 1 | Later date. A last 32°F on or after this day is uncommon. |
First 32°F in fall
NCEI’s probability is the chance the first autumn minimum of 32°F or lower occurs on or before the date.
| Probability | Date | How to read it |
|---|---|---|
| 10% | November 1 | Earlier date. A first 32°F on or before this day is uncommon. |
| 50% | November 17 | Median. |
| 90% | December 6 | Later date. A first 32°F on or before this day is common. |
32°F growing-season length
Days between the last spring 32°F and the first autumn 32°F. The figure is a length the season meets or exceeds at that probability, from NCEI, not a subtraction done on this site.
| Probability the season is at least this long | Days |
|---|---|
| 10% | 278 |
| 50% | 247 |
| 90% | 222 |
28°F threshold
| 10% | 50% | 90% | |
|---|---|---|---|
| Last, on or after | March 10 | February 18 | January 7 |
| First, on or before | November 12 | December 2 | December 30 |
| Season at least | 334 days | 295 days | 260 days |
36°F threshold
| 10% | 50% | 90% | |
|---|---|---|---|
| Last, on or after | April 28 | April 3 | March 17 |
| First, on or before | October 17 | October 31 | November 17 |
| Season at least | 232 days | 209 days | 182 days |
Station SEATTLE BOEING FLD, WA US (USW00024234). Completeness flag R, 18 years used for the 32°F dates. NCEI’s annual probability of at least one day at or below 32°F is 100%. Freeze dates are conditional on that threshold occurring. Elevation 6.1 m. The same probability language applies to the 28°F and 36°F rows when those dates passed the same quality checks.