Frost dates for 84535Monticello, UT
The average last spring frost in Monticello is May 19 and the average first fall frost is October 2, giving a typical growing season of about 133 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 19
- Average first fall frost
- Oct 2
- Growing season
- 133 days
Safer after Jun 6 (1-in-10 risk)
Possible by Sep 20 (1-in-10 risk)
Last frost typically in 197 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 18 · Jun 1 · Jun 17 | Sep 11 · Sep 24 · Oct 5 | 112 days | 100% |
| Frost / freeze (32°F) | May 3 · May 19 · Jun 6 | Sep 20 · Oct 2 · Oct 15 | 133 days | 100% |
| Hard freeze (28°F) | Apr 21 · May 6 · May 23 | Sep 28 · Oct 12 · Oct 24 | 158 days | 100% |
Planting calendar for Monticello
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 18 – Jun 24 |
| Tomatoes | Transplant outdoors | Jun 4 – Jun 12 |
| Peppers | Start seeds indoors | Apr 18 – May 19 |
| Peppers | Transplant outdoors | Jun 18 – Jul 19 |
| Eggplant | Start seeds indoors | May 5 – Jun 3 |
| Eggplant | Transplant outdoors | Jun 18 – Jul 19 |
| Cucumbers | Sow outdoors | Jun 18 – Jun 22 |
| Summer squash | Sow outdoors | Jun 4 – Jul 19 |
| Winter squash & pumpkins | Sow outdoors | Jun 18 – Jul 19 |
| Snap beans | Sow outdoors | Jun 4 – Jul 15 |
| Sweet corn | Sow outdoors | Jun 4 – Jun 12 |
| Watermelon & cantaloupe | Sow outdoors | Jun 18 – Jul 19 |
| Okra | Sow outdoors | Jun 11 – Jul 4 |
| Peas | Sow outdoors (spring) | Apr 18 – Jun 3 |
| Potatoes | Plant outdoors (spring) | Apr 18 – Jun 18 |
| Onions | Start seeds indoors (spring) | Mar 7 – Apr 3 |
| Onions | Transplant outdoors (spring) | May 5 – Jun 3 |
| Broccoli | Start seeds indoors (spring) | Mar 31 – May 4 |
| Broccoli | Transplant outdoors (spring) | May 5 – Jun 3 |
| Broccoli | Start seeds indoors (fall) | Jun 2 – Jun 12 |
| Broccoli | Transplant outdoors (fall) | Jul 2 – Jul 13 |
| Cabbage | Start seeds indoors (spring) | Mar 21 – Apr 18 |
| Cabbage | Transplant outdoors (spring) | Apr 18 – May 19 |
| Cabbage | Start seeds indoors (fall) | May 23 – Jun 22 |
| Cabbage | Transplant outdoors (fall) | Jun 22 – Jul 23 |
| Leaf lettuce | Sow outdoors (spring) | Apr 18 – Jul 4 |
| Leaf lettuce | Sow outdoors (fall) | Jun 22 – Aug 8 |
| Spinach | Sow outdoors (spring) | Apr 11 – May 25 |
| Spinach | Sow outdoors (fall) | Jul 9 – Aug 13 |
| Radishes | Sow outdoors (spring) | Apr 18 – Jun 8 |
| Radishes | Sow outdoors (fall) | Jun 22 – Aug 23 |
| Kale | Sow outdoors (spring) | May 5 – May 25 |
| Kale | Sow outdoors (fall) | Jun 15 – Jul 23 |
| Carrots | Sow outdoors (spring) | May 19 – Jul 4 |
| Carrots | Sow outdoors (fall) | May 23 – Jul 8 |
| Garlic | Plant outdoors (fall) | Sep 22 – Oct 23 |
Where these dates come from
ZIP code 84535 is matched to the NOAA station Monticello 2E, UT, 5.4 km away, at 6,820 ft elevation (21 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Monticello 2E, UT (used) | 6,820 ft | May 19 | Oct 2 |
| Monticello #2, UT | 7,086 ft | May 17 | Oct 7 |
| Northdale, CO | 6,681 ft | Jun 3 | Sep 25 |
| Cedar Pt, UT | 6,760 ft | May 16 | Oct 11 |
Frost dates near Monticello
- Egnar, CO 81325 · last Jun 3, first Sep 25
- Dove Creek, CO 81324 · last Jun 3, first Sep 25
- Blanding, UT 84511 · last Apr 28, first Oct 21
- La Sal, UT 84530 · last May 17, first Oct 6
- Bedrock, CO 81411 · last May 17, first Oct 6
- Cahone, CO 81320 · last May 17, first Oct 9
- Pleasant View, CO 81331 · last May 17, first Oct 9
- Paradox, CO 81429 · last May 11, first Oct 5
Frequently asked questions
- When is the last frost in Monticello, UT?
- For ZIP code 84535, the average last spring frost (32°F) is May 19, based on NOAA 1991-2020 climate normals for the Monticello 2E, UT weather station. There is a 1-in-10 chance of a frost after June 6.
- When is the first frost in Monticello, UT?
- The average first fall frost (32°F) is October 2. There is a 1-in-10 chance of frost by September 20, so tender plants are at risk from that point on.
- How long is the growing season in 84535?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 133 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.