Frost dates for 97902Arock, OR
The average last spring frost in Arock is June 11 and the average first fall frost is September 10, giving a typical growing season of about 88 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Jun 11
- Average first fall frost
- Sep 10
- Growing season
- 88 days
Safer after Jul 3 (1-in-10 risk)
Possible by Aug 27 (1-in-10 risk)
Last frost typically in 221 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) | — | — | 64 days | 100% |
| Frost / freeze (32°F) | May 20 · Jun 11 · Jul 3 | Aug 27 · Sep 10 · Sep 24 | 88 days | 100% |
| Hard freeze (28°F) | May 4 · May 22 · Jun 19 | Sep 7 · Sep 21 · Oct 5 | 118 days | 100% |
Planting calendar for Arock
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 | May 11 – Jul 17 |
| Tomatoes | Transplant outdoors | Jun 27 – May 21 |
| Peppers | Start seeds indoors | May 11 – Jun 11 |
| Peppers | Transplant outdoors | Jul 11 – Aug 11 |
| Eggplant | Start seeds indoors | May 28 – Jun 26 |
| Eggplant | Transplant outdoors | Jul 11 – Aug 11 |
| Cucumbers | Sow outdoors | Jul 11 – May 31 |
| Summer squash | Sow outdoors | Jun 27 – Aug 11 |
| Winter squash & pumpkins | Sow outdoors | Jul 11 – Aug 11 |
| Snap beans | Sow outdoors | Jun 27 – Jun 23 |
| Sweet corn | Sow outdoors | Jun 27 – May 21 |
| Watermelon & cantaloupe | Sow outdoors | Jul 11 – Aug 11 |
| Okra | Sow outdoors | Jul 4 – Jul 27 |
| Peas | Sow outdoors (spring) | May 11 – Jun 26 |
| Potatoes | Plant outdoors (spring) | May 11 – Jul 11 |
| Onions | Start seeds indoors (spring) | Mar 30 – Apr 26 |
| Onions | Transplant outdoors (spring) | May 28 – Jun 26 |
| Broccoli | Start seeds indoors (spring) | Apr 23 – May 27 |
| Broccoli | Transplant outdoors (spring) | May 28 – Jun 26 |
| Broccoli | Start seeds indoors (fall) | May 11 – May 21 |
| Broccoli | Transplant outdoors (fall) | Jun 10 – Jun 21 |
| Cabbage | Start seeds indoors (spring) | Apr 13 – May 11 |
| Cabbage | Transplant outdoors (spring) | May 11 – Jun 11 |
| Cabbage | Start seeds indoors (fall) | May 1 – May 31 |
| Cabbage | Transplant outdoors (fall) | May 31 – Jul 1 |
| Leaf lettuce | Sow outdoors (spring) | May 11 – Jul 27 |
| Leaf lettuce | Sow outdoors (fall) | May 31 – Jul 17 |
| Spinach | Sow outdoors (spring) | May 4 – Jun 17 |
| Spinach | Sow outdoors (fall) | Jun 17 – Jul 22 |
| Radishes | Sow outdoors (spring) | May 11 – Jul 1 |
| Radishes | Sow outdoors (fall) | May 31 – Aug 1 |
| Kale | Sow outdoors (spring) | May 28 – Jun 17 |
| Kale | Sow outdoors (fall) | May 24 – Jul 1 |
| Carrots | Sow outdoors (spring) | Jun 11 – Jul 27 |
| Carrots | Sow outdoors (fall) | May 1 – Jun 16 |
| Garlic | Plant outdoors (fall) | Aug 31 – Oct 1 |
Where these dates come from
ZIP code 97902 is matched to the NOAA station Rome 2 Nw, OR, 14.4 km away, at 3,405 ft elevation (437 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Rome 2 Nw, OR (used) | 3,405 ft | Jun 11 | Sep 10 |
| Sheaville 1 Se, OR | 4,620 ft | May 22 | Sep 28 |
| Rome St Ap, OR | 4,050 ft | May 26 | Sep 21 |
| Silver City 5 W, ID | 6,160 ft | May 31 | Oct 6 |
Frost dates near Arock
- Jordan Valley, OR 97910 · last May 22, first Sep 28
- Murphy, ID 83650 · last May 31, first Oct 6
- Riverside, OR 97917 · last Jun 7, first Sep 6
- Marsing, ID 83639 · last Apr 24, first Oct 9
- Adrian, OR 97901 · last Apr 24, first Oct 9
- Homedale, ID 83628 · last Apr 24, first Oct 9
- Melba, ID 83641 · last Apr 29, first Oct 13
- Wilder, ID 83676 · last Apr 24, first Oct 9
Frequently asked questions
- When is the last frost in Arock, OR?
- For ZIP code 97902, the average last spring frost (32°F) is June 11, based on NOAA 1991-2020 climate normals for the Rome 2 Nw, OR weather station. There is a 1-in-10 chance of a frost after July 3.
- When is the first frost in Arock, OR?
- The average first fall frost (32°F) is September 10. There is a 1-in-10 chance of frost by August 27, so tender plants are at risk from that point on.
- How long is the growing season in 97902?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 88 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.