Frost dates for 85342Morristown, AZ
The average last spring frost in Morristown is March 7 and the average first fall frost is November 20, giving a typical growing season of about 254 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Mar 7
- Average first fall frost
- Nov 20
- Growing season
- 254 days
Safer after Apr 8 (1-in-10 risk)
Possible by Nov 4 (1-in-10 risk)
First frost typically in 19 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 11 · Apr 3 · Apr 25 | Oct 24 · Nov 9 · Nov 22 | 219 days | 100% |
| Frost / freeze (32°F) | Feb 14 · Mar 7 · Apr 8 | Nov 4 · Nov 20 · Dec 5 | 254 days | 100% |
| Hard freeze (28°F) | Jan 15 · Feb 14 · Mar 6 | Nov 14 · Dec 2 · Dec 22 | 290 days | 100% |
Planting calendar for Morristown
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 4 – Apr 12 |
| Tomatoes | Transplant outdoors | Mar 23 – Jul 31 |
| Peppers | Start seeds indoors | Feb 4 – Mar 7 |
| Peppers | Transplant outdoors | Apr 6 – May 7 |
| Eggplant | Start seeds indoors | Feb 21 – Mar 22 |
| Eggplant | Transplant outdoors | Apr 6 – May 7 |
| Cucumbers | Sow outdoors | Apr 6 – Aug 10 |
| Summer squash | Sow outdoors | Mar 23 – May 7 |
| Winter squash & pumpkins | Sow outdoors | Apr 6 – May 7 |
| Snap beans | Sow outdoors | Mar 23 – Sep 2 |
| Sweet corn | Sow outdoors | Mar 23 – Jul 31 |
| Watermelon & cantaloupe | Sow outdoors | Apr 6 – May 7 |
| Okra | Sow outdoors | Mar 30 – Apr 22 |
| Peas | Sow outdoors (spring) | Feb 4 – Mar 22 |
| Potatoes | Plant outdoors (spring) | Feb 4 – Apr 6 |
| Onions | Start seeds indoors (spring) | Dec 24 – Jan 20 |
| Onions | Transplant outdoors (spring) | Feb 21 – Mar 22 |
| Broccoli | Start seeds indoors (spring) | Jan 17 – Feb 20 |
| Broccoli | Transplant outdoors (spring) | Feb 21 – Mar 22 |
| Broccoli | Start seeds indoors (fall) | Jul 21 – Jul 31 |
| Broccoli | Transplant outdoors (fall) | Aug 20 – Aug 31 |
| Cabbage | Start seeds indoors (spring) | Jan 7 – Feb 4 |
| Cabbage | Transplant outdoors (spring) | Feb 4 – Mar 7 |
| Cabbage | Start seeds indoors (fall) | Jul 11 – Aug 10 |
| Cabbage | Transplant outdoors (fall) | Aug 10 – Sep 10 |
| Leaf lettuce | Sow outdoors (spring) | Feb 4 – Apr 22 |
| Leaf lettuce | Sow outdoors (fall) | Aug 10 – Sep 26 |
| Spinach | Sow outdoors (spring) | Jan 28 – Mar 13 |
| Spinach | Sow outdoors (fall) | Aug 27 – Oct 1 |
| Radishes | Sow outdoors (spring) | Feb 4 – Mar 27 |
| Radishes | Sow outdoors (fall) | Aug 10 – Oct 11 |
| Kale | Sow outdoors (spring) | Feb 21 – Mar 13 |
| Kale | Sow outdoors (fall) | Aug 3 – Sep 10 |
| Carrots | Sow outdoors (spring) | Mar 7 – Apr 22 |
| Carrots | Sow outdoors (fall) | Jul 11 – Aug 26 |
| Garlic | Plant outdoors (fall) | Nov 10 – Dec 11 |
Where these dates come from
ZIP code 85342 is matched to the NOAA station Wickenburg, AZ, 17.4 km away, at 2,095 ft elevation (107 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Wickenburg, AZ (used) | 2,095 ft | Mar 7 | Nov 20 |
| Wittmann 1Se, AZ | 1,683 ft | Feb 5 | Dec 11 |
| Castle Hot Springs, AZ | 1,990 ft | Jan 15 | Dec 22 |
| Youngtown, AZ | 1,135 ft | Jan 20 | Dec 15 |
Frost dates near Morristown
- Wittmann, AZ 85361 · last Feb 5, first Dec 11
- Wickenburg, AZ 85358 · last Mar 7, first Nov 20
- Surprise, AZ 85387 · last Feb 5, first Dec 11
- Sun City West, AZ 85375 · last Jan 20, first Dec 15
- Sun City, AZ 85373 · last Jan 20, first Dec 15
- Waddell, AZ 85355 · last Jan 20, first Dec 15
- Congress, AZ 85332 · last Mar 7, first Nov 20
- Peoria, AZ 85383 · last Jan 8, first Dec 25
Frequently asked questions
- When is the last frost in Morristown, AZ?
- For ZIP code 85342, the average last spring frost (32°F) is March 7, based on NOAA 1991-2020 climate normals for the Wickenburg, AZ weather station. There is a 1-in-10 chance of a frost after April 8.
- When is the first frost in Morristown, AZ?
- The average first fall frost (32°F) is November 20. There is a 1-in-10 chance of frost by November 4, so tender plants are at risk from that point on.
- How long is the growing season in 85342?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 254 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.