Frost dates for 98057Renton, WA
The average last spring frost in Renton is March 13 and the average first fall frost is November 16, giving a typical growing season of about 248 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Mar 13
- Average first fall frost
- Nov 16
- Growing season
- 248 days
Safer after Mar 31 (1-in-10 risk)
Possible by Oct 29 (1-in-10 risk)
First frost typically in 14 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | Mar 21 · Apr 6 · Apr 25 | Oct 17 · Oct 31 · Nov 17 | 207 days | 100% |
| Frost / freeze (32°F) | Feb 19 · Mar 13 · Mar 31 | Oct 29 · Nov 16 · Dec 9 | 248 days | 100% |
| Hard freeze (28°F) | Jan 1 · Feb 13 · Mar 6 | Nov 11 · Dec 6 · Jan 9 | 301 days | 98% |
Planting calendar for Renton
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Feb 10 – Apr 18 |
| Tomatoes | Transplant outdoors | Mar 29 – Jul 27 |
| Peppers | Start seeds indoors | Feb 10 – Mar 13 |
| Peppers | Transplant outdoors | Apr 12 – May 13 |
| Eggplant | Start seeds indoors | Feb 27 – Mar 28 |
| Eggplant | Transplant outdoors | Apr 12 – May 13 |
| Cucumbers | Sow outdoors | Apr 12 – Aug 6 |
| Summer squash | Sow outdoors | Mar 29 – May 13 |
| Winter squash & pumpkins | Sow outdoors | Apr 12 – May 13 |
| Snap beans | Sow outdoors | Mar 29 – Aug 29 |
| Sweet corn | Sow outdoors | Mar 29 – Jul 27 |
| Watermelon & cantaloupe | Sow outdoors | Apr 12 – May 13 |
| Okra | Sow outdoors | Apr 5 – Apr 28 |
| Peas | Sow outdoors (spring) | Feb 10 – Mar 28 |
| Potatoes | Plant outdoors (spring) | Feb 10 – Apr 12 |
| Onions | Start seeds indoors (spring) | Dec 30 – Jan 26 |
| Onions | Transplant outdoors (spring) | Feb 27 – Mar 28 |
| Broccoli | Start seeds indoors (spring) | Jan 23 – Feb 26 |
| Broccoli | Transplant outdoors (spring) | Feb 27 – Mar 28 |
| Broccoli | Start seeds indoors (fall) | Jul 17 – Jul 27 |
| Broccoli | Transplant outdoors (fall) | Aug 16 – Aug 27 |
| Cabbage | Start seeds indoors (spring) | Jan 13 – Feb 10 |
| Cabbage | Transplant outdoors (spring) | Feb 10 – Mar 13 |
| Cabbage | Start seeds indoors (fall) | Jul 7 – Aug 6 |
| Cabbage | Transplant outdoors (fall) | Aug 6 – Sep 6 |
| Leaf lettuce | Sow outdoors (spring) | Feb 10 – Apr 28 |
| Leaf lettuce | Sow outdoors (fall) | Aug 6 – Sep 22 |
| Spinach | Sow outdoors (spring) | Feb 3 – Mar 19 |
| Spinach | Sow outdoors (fall) | Aug 23 – Sep 27 |
| Radishes | Sow outdoors (spring) | Feb 10 – Apr 2 |
| Radishes | Sow outdoors (fall) | Aug 6 – Oct 7 |
| Kale | Sow outdoors (spring) | Feb 27 – Mar 19 |
| Kale | Sow outdoors (fall) | Jul 30 – Sep 6 |
| Carrots | Sow outdoors (spring) | Mar 13 – Apr 28 |
| Carrots | Sow outdoors (fall) | Jul 7 – Aug 22 |
| Garlic | Plant outdoors (fall) | Nov 6 – Dec 7 |
Where these dates come from
ZIP code 98057 is matched to the NOAA station Renton Muni Ap, WA, 2.5 km away, at 29 ft elevation (3 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Renton Muni Ap, WA (used) | 29 ft | Mar 13 | Nov 16 |
| Kent, WA | 30 ft | Mar 20 | Nov 10 |
| Seattle Tacoma Intl Ap, WA | 370 ft | Mar 2 | Nov 23 |
| Seattle Boeing Fld, WA | 20 ft | Mar 13 | Nov 17 |
Frost dates near Renton
- Renton, WA 98055 · last Mar 13, first Nov 16
- Seattle, WA 98178 · last Mar 2, first Nov 23
- Kent, WA 98030 · last Mar 2, first Nov 23
- Mercer Island, WA 98040 · last Mar 13, first Nov 17
- Seahurst, WA 98062 · last Mar 2, first Nov 23
- Bellevue, WA 98006 · last Apr 20, first Oct 25
- Maple Valley, WA 98038 · last Apr 20, first Oct 25
- Issaquah, WA 98027 · last Apr 23, first Nov 1
Frequently asked questions
- When is the last frost in Renton, WA?
- For ZIP code 98057, the average last spring frost (32°F) is March 13, based on NOAA 1991-2020 climate normals for the Renton Muni Ap, WA weather station. There is a 1-in-10 chance of a frost after March 31.
- When is the first frost in Renton, WA?
- The average first fall frost (32°F) is November 16. There is a 1-in-10 chance of frost by October 29, so tender plants are at risk from that point on.
- How long is the growing season in 98057?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 248 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.