Frost dates for 85920Alpine, AZ
The average last spring frost in Alpine is June 15 and the average first fall frost is September 21, giving a typical growing season of about 96 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Jun 15
- Average first fall frost
- Sep 21
- Growing season
- 96 days
Safer after Jun 30 (1-in-10 risk)
Possible by Sep 7 (1-in-10 risk)
Last frost typically in 224 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) | Jun 14 · Jun 28 · Jul 12 | Aug 29 · Sep 10 · Sep 22 | 73 days | 100% |
| Frost / freeze (32°F) | Jun 2 · Jun 15 · Jun 30 | Sep 7 · Sep 21 · Oct 1 | 96 days | 100% |
| Hard freeze (28°F) | May 19 · Jun 3 · Jun 19 | Sep 16 · Sep 28 · Oct 11 | 116 days | 100% |
Planting calendar for Alpine
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 15 – Jul 21 |
| Tomatoes | Transplant outdoors | Jul 1 – Jun 1 |
| Peppers | Start seeds indoors | May 15 – Jun 15 |
| Peppers | Transplant outdoors | Jul 15 – Aug 15 |
| Eggplant | Start seeds indoors | Jun 1 – Jun 30 |
| Eggplant | Transplant outdoors | Jul 15 – Aug 15 |
| Cucumbers | Sow outdoors | Jul 15 – Jun 11 |
| Summer squash | Sow outdoors | Jul 1 – Aug 15 |
| Winter squash & pumpkins | Sow outdoors | Jul 15 – Aug 15 |
| Snap beans | Sow outdoors | Jul 1 – Jul 4 |
| Sweet corn | Sow outdoors | Jul 1 – Jun 1 |
| Watermelon & cantaloupe | Sow outdoors | Jul 15 – Aug 15 |
| Okra | Sow outdoors | Jul 8 – Jul 31 |
| Peas | Sow outdoors (spring) | May 15 – Jun 30 |
| Potatoes | Plant outdoors (spring) | May 15 – Jul 15 |
| Onions | Start seeds indoors (spring) | Apr 3 – Apr 30 |
| Onions | Transplant outdoors (spring) | Jun 1 – Jun 30 |
| Broccoli | Start seeds indoors (spring) | Apr 27 – May 31 |
| Broccoli | Transplant outdoors (spring) | Jun 1 – Jun 30 |
| Broccoli | Start seeds indoors (fall) | May 22 – Jun 1 |
| Broccoli | Transplant outdoors (fall) | Jun 21 – Jul 2 |
| Cabbage | Start seeds indoors (spring) | Apr 17 – May 15 |
| Cabbage | Transplant outdoors (spring) | May 15 – Jun 15 |
| Cabbage | Start seeds indoors (fall) | May 12 – Jun 11 |
| Cabbage | Transplant outdoors (fall) | Jun 11 – Jul 12 |
| Leaf lettuce | Sow outdoors (spring) | May 15 – Jul 31 |
| Leaf lettuce | Sow outdoors (fall) | Jun 11 – Jul 28 |
| Spinach | Sow outdoors (spring) | May 8 – Jun 21 |
| Spinach | Sow outdoors (fall) | Jun 28 – Aug 2 |
| Radishes | Sow outdoors (spring) | May 15 – Jul 5 |
| Radishes | Sow outdoors (fall) | Jun 11 – Aug 12 |
| Kale | Sow outdoors (spring) | Jun 1 – Jun 21 |
| Kale | Sow outdoors (fall) | Jun 4 – Jul 12 |
| Carrots | Sow outdoors (spring) | Jun 15 – Jul 31 |
| Carrots | Sow outdoors (fall) | May 12 – Jun 27 |
| Garlic | Plant outdoors (fall) | Sep 11 – Oct 12 |
Where these dates come from
ZIP code 85920 is matched to the NOAA station Alpine, AZ, 2.9 km away, at 8,050 ft elevation (54 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Alpine, AZ (used) | 8,050 ft | Jun 15 | Sep 21 |
| Luna Rs, NM | 7,050 ft | Jun 17 | Sep 21 |
| Reserve Rs, NM | 5,847 ft | May 30 | Oct 3 |
| Springerville, AZ | 6,998 ft | Jun 1 | Sep 26 |
Frost dates near Alpine
- Nutrioso, AZ 85932 · last Jun 15, first Sep 21
- Luna, NM 87824 · last Jun 17, first Sep 21
- Blue, AZ 85922 · last Jun 17, first Sep 21
- Eagar, AZ 85925 · last Jun 1, first Sep 26
- Reserve, NM 87830 · last May 30, first Oct 3
- Greer, AZ 85927 · last Jun 5, first Sep 29
- Springerville, AZ 85938 · last Jun 1, first Sep 26
- Aragon, NM 87820 · last Jun 17, first Sep 21
Frequently asked questions
- When is the last frost in Alpine, AZ?
- For ZIP code 85920, the average last spring frost (32°F) is June 15, based on NOAA 1991-2020 climate normals for the Alpine, AZ weather station. There is a 1-in-10 chance of a frost after June 30.
- When is the first frost in Alpine, AZ?
- The average first fall frost (32°F) is September 21. There is a 1-in-10 chance of frost by September 7, so tender plants are at risk from that point on.
- How long is the growing season in 85920?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 96 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.