Frost dates for 97027Gladstone, OR
The average last spring frost in Gladstone is March 18 and the average first fall frost is November 18, giving a typical growing season of about 244 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Mar 18
- Average first fall frost
- Nov 18
- Growing season
- 244 days
Safer after Apr 11 (1-in-10 risk)
Possible by Oct 30 (1-in-10 risk)
First frost typically in 15 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 26 · Apr 15 · May 4 | Oct 16 · Oct 31 · Nov 20 | 198 days | 100% |
| Frost / freeze (32°F) | Feb 19 · Mar 18 · Apr 11 | Oct 30 · Nov 18 · Dec 12 | 244 days | 100% |
| Hard freeze (28°F) | Jan 1 · Feb 12 · Mar 7 | Nov 16 · Dec 8 · Jan 5 | 302 days | 97% |
Planting calendar for Gladstone
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 15 – Apr 23 |
| Tomatoes | Transplant outdoors | Apr 3 – Jul 29 |
| Peppers | Start seeds indoors | Feb 15 – Mar 18 |
| Peppers | Transplant outdoors | Apr 17 – May 18 |
| Eggplant | Start seeds indoors | Mar 4 – Apr 2 |
| Eggplant | Transplant outdoors | Apr 17 – May 18 |
| Cucumbers | Sow outdoors | Apr 17 – Aug 8 |
| Summer squash | Sow outdoors | Apr 3 – May 18 |
| Winter squash & pumpkins | Sow outdoors | Apr 17 – May 18 |
| Snap beans | Sow outdoors | Apr 3 – Aug 31 |
| Sweet corn | Sow outdoors | Apr 3 – Jul 29 |
| Watermelon & cantaloupe | Sow outdoors | Apr 17 – May 18 |
| Okra | Sow outdoors | Apr 10 – May 3 |
| Peas | Sow outdoors (spring) | Feb 15 – Apr 2 |
| Potatoes | Plant outdoors (spring) | Feb 15 – Apr 17 |
| Onions | Start seeds indoors (spring) | Jan 4 – Jan 31 |
| Onions | Transplant outdoors (spring) | Mar 4 – Apr 2 |
| Broccoli | Start seeds indoors (spring) | Jan 28 – Mar 3 |
| Broccoli | Transplant outdoors (spring) | Mar 4 – Apr 2 |
| Broccoli | Start seeds indoors (fall) | Jul 19 – Jul 29 |
| Broccoli | Transplant outdoors (fall) | Aug 18 – Aug 29 |
| Cabbage | Start seeds indoors (spring) | Jan 18 – Feb 15 |
| Cabbage | Transplant outdoors (spring) | Feb 15 – Mar 18 |
| Cabbage | Start seeds indoors (fall) | Jul 9 – Aug 8 |
| Cabbage | Transplant outdoors (fall) | Aug 8 – Sep 8 |
| Leaf lettuce | Sow outdoors (spring) | Feb 15 – May 3 |
| Leaf lettuce | Sow outdoors (fall) | Aug 8 – Sep 24 |
| Spinach | Sow outdoors (spring) | Feb 8 – Mar 24 |
| Spinach | Sow outdoors (fall) | Aug 25 – Sep 29 |
| Radishes | Sow outdoors (spring) | Feb 15 – Apr 7 |
| Radishes | Sow outdoors (fall) | Aug 8 – Oct 9 |
| Kale | Sow outdoors (spring) | Mar 4 – Mar 24 |
| Kale | Sow outdoors (fall) | Aug 1 – Sep 8 |
| Carrots | Sow outdoors (spring) | Mar 18 – May 3 |
| Carrots | Sow outdoors (fall) | Jul 9 – Aug 24 |
| Garlic | Plant outdoors (fall) | Nov 8 – Dec 9 |
Where these dates come from
ZIP code 97027 is matched to the NOAA station Oregon City, OR, 4 km away, at 167 ft elevation (13 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Oregon City, OR (used) | 167 ft | Mar 18 | Nov 18 |
| Portland Kgw-Tv, OR | 159 ft | Feb 25 | Dec 1 |
| N Willamette Exp Stn, OR | 150 ft | Mar 18 | Nov 13 |
| Beaverton 2 Ssw, OR | 270 ft | Apr 1 | Nov 6 |
Frost dates near Gladstone
- Portland, OR 97267 · last Mar 18, first Nov 18
- Marylhurst, OR 97036 · last Mar 18, first Nov 18
- West Linn, OR 97068 · last Mar 18, first Nov 18
- Oregon City, OR 97045 · last Mar 18, first Nov 18
- Clackamas, OR 97015 · last Mar 18, first Nov 18
- Happy Valley, OR 97086 · last Mar 18, first Nov 18
- Lake Oswego, OR 97034 · last Mar 18, first Nov 18
- Damascus, OR 97089 · last Mar 27, first Nov 14
Frequently asked questions
- When is the last frost in Gladstone, OR?
- For ZIP code 97027, the average last spring frost (32°F) is March 18, based on NOAA 1991-2020 climate normals for the Oregon City, OR weather station. There is a 1-in-10 chance of a frost after April 11.
- When is the first frost in Gladstone, OR?
- The average first fall frost (32°F) is November 18. There is a 1-in-10 chance of frost by October 30, so tender plants are at risk from that point on.
- How long is the growing season in 97027?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 244 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.