Frost dates for 85936Saint Johns, AZ
The average last spring frost in Saint Johns is May 3 and the average first fall frost is October 10, giving a typical growing season of about 160 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 3
- Average first fall frost
- Oct 10
- Growing season
- 160 days
Safer after May 19 (1-in-10 risk)
Possible by Sep 30 (1-in-10 risk)
Last frost typically in 188 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) | May 1 · May 15 · May 31 | Sep 21 · Oct 3 · Oct 15 | 140 days | 100% |
| Frost / freeze (32°F) | Apr 20 · May 3 · May 19 | Sep 30 · Oct 10 · Oct 25 | 160 days | 100% |
| Hard freeze (28°F) | Apr 6 · Apr 21 · May 7 | Oct 6 · Oct 20 · Nov 3 | 180 days | 100% |
Planting calendar for Saint Johns
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 | Apr 2 – Jun 8 |
| Tomatoes | Transplant outdoors | May 19 – Jun 20 |
| Peppers | Start seeds indoors | Apr 2 – May 3 |
| Peppers | Transplant outdoors | Jun 2 – Jul 3 |
| Eggplant | Start seeds indoors | Apr 19 – May 18 |
| Eggplant | Transplant outdoors | Jun 2 – Jul 3 |
| Cucumbers | Sow outdoors | Jun 2 – Jun 30 |
| Summer squash | Sow outdoors | May 19 – Jul 3 |
| Winter squash & pumpkins | Sow outdoors | Jun 2 – Jul 3 |
| Snap beans | Sow outdoors | May 19 – Jul 23 |
| Sweet corn | Sow outdoors | May 19 – Jun 20 |
| Watermelon & cantaloupe | Sow outdoors | Jun 2 – Jul 3 |
| Okra | Sow outdoors | May 26 – Jun 18 |
| Peas | Sow outdoors (spring) | Apr 2 – May 18 |
| Potatoes | Plant outdoors (spring) | Apr 2 – Jun 2 |
| Onions | Start seeds indoors (spring) | Feb 19 – Mar 18 |
| Onions | Transplant outdoors (spring) | Apr 19 – May 18 |
| Broccoli | Start seeds indoors (spring) | Mar 15 – Apr 18 |
| Broccoli | Transplant outdoors (spring) | Apr 19 – May 18 |
| Broccoli | Start seeds indoors (fall) | Jun 10 – Jun 20 |
| Broccoli | Transplant outdoors (fall) | Jul 10 – Jul 21 |
| Cabbage | Start seeds indoors (spring) | Mar 5 – Apr 2 |
| Cabbage | Transplant outdoors (spring) | Apr 2 – May 3 |
| Cabbage | Start seeds indoors (fall) | May 31 – Jun 30 |
| Cabbage | Transplant outdoors (fall) | Jun 30 – Jul 31 |
| Leaf lettuce | Sow outdoors (spring) | Apr 2 – Jun 18 |
| Leaf lettuce | Sow outdoors (fall) | Jun 30 – Aug 16 |
| Spinach | Sow outdoors (spring) | Mar 26 – May 9 |
| Spinach | Sow outdoors (fall) | Jul 17 – Aug 21 |
| Radishes | Sow outdoors (spring) | Apr 2 – May 23 |
| Radishes | Sow outdoors (fall) | Jun 30 – Aug 31 |
| Kale | Sow outdoors (spring) | Apr 19 – May 9 |
| Kale | Sow outdoors (fall) | Jun 23 – Jul 31 |
| Carrots | Sow outdoors (spring) | May 3 – Jun 18 |
| Carrots | Sow outdoors (fall) | May 31 – Jul 16 |
| Garlic | Plant outdoors (fall) | Sep 30 – Oct 31 |
Where these dates come from
ZIP code 85936 is matched to the NOAA station St Johns Industrial Ap, AZ, 1.9 km away, at 5,733 ft elevation (18 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| St Johns Industrial Ap, AZ (used) | 5,733 ft | May 3 | Oct 10 |
| Saint Johns, AZ | 5,790 ft | May 2 | Oct 14 |
| Springerville, AZ | 6,998 ft | Jun 1 | Sep 26 |
| Greer, AZ | 8,275 ft | Jun 5 | Sep 29 |
Frost dates near Saint Johns
- Concho, AZ 85924 · last May 2, first Oct 14
- Springerville, AZ 85938 · last Jun 1, first Sep 26
- Vernon, AZ 85940 · last May 22, first Oct 6
- Eagar, AZ 85925 · last Jun 1, first Sep 26
- Greer, AZ 85927 · last Jun 5, first Sep 29
- Show Low, AZ 85901 · last May 5, first Oct 15
- Quemado, NM 87829 · last Jun 1, first Sep 29
- Nutrioso, AZ 85932 · last Jun 15, first Sep 21
Frequently asked questions
- When is the last frost in Saint Johns, AZ?
- For ZIP code 85936, the average last spring frost (32°F) is May 3, based on NOAA 1991-2020 climate normals for the St Johns Industrial Ap, AZ weather station. There is a 1-in-10 chance of a frost after May 19.
- When is the first frost in Saint Johns, AZ?
- The average first fall frost (32°F) is October 10. There is a 1-in-10 chance of frost by September 30, so tender plants are at risk from that point on.
- How long is the growing season in 85936?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 160 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.