Frost dates for 80134Parker, CO
The average last spring frost in Parker is May 9 and the average first fall frost is October 2, giving a typical growing season of about 143 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 9
- Average first fall frost
- Oct 2
- Growing season
- 143 days
Safer after May 24 (1-in-10 risk)
Possible by Sep 17 (1-in-10 risk)
Last frost typically in 194 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 9 · May 21 · Jun 6 | Sep 11 · Sep 25 · Oct 7 | 124 days | 100% |
| Frost / freeze (32°F) | Apr 30 · May 9 · May 24 | Sep 17 · Oct 2 · Oct 16 | 143 days | 100% |
| Hard freeze (28°F) | Apr 17 · May 1 · May 14 | Sep 26 · Oct 12 · Oct 25 | 161 days | 100% |
Planting calendar for Parker
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 8 – Jun 14 |
| Tomatoes | Transplant outdoors | May 25 – Jun 12 |
| Peppers | Start seeds indoors | Apr 8 – May 9 |
| Peppers | Transplant outdoors | Jun 8 – Jul 9 |
| Eggplant | Start seeds indoors | Apr 25 – May 24 |
| Eggplant | Transplant outdoors | Jun 8 – Jul 9 |
| Cucumbers | Sow outdoors | Jun 8 – Jun 22 |
| Summer squash | Sow outdoors | May 25 – Jul 9 |
| Winter squash & pumpkins | Sow outdoors | Jun 8 – Jul 9 |
| Snap beans | Sow outdoors | May 25 – Jul 15 |
| Sweet corn | Sow outdoors | May 25 – Jun 12 |
| Watermelon & cantaloupe | Sow outdoors | Jun 8 – Jul 9 |
| Okra | Sow outdoors | Jun 1 – Jun 24 |
| Peas | Sow outdoors (spring) | Apr 8 – May 24 |
| Potatoes | Plant outdoors (spring) | Apr 8 – Jun 8 |
| Onions | Start seeds indoors (spring) | Feb 25 – Mar 24 |
| Onions | Transplant outdoors (spring) | Apr 25 – May 24 |
| Broccoli | Start seeds indoors (spring) | Mar 21 – Apr 24 |
| Broccoli | Transplant outdoors (spring) | Apr 25 – May 24 |
| Broccoli | Start seeds indoors (fall) | Jun 2 – Jun 12 |
| Broccoli | Transplant outdoors (fall) | Jul 2 – Jul 13 |
| Cabbage | Start seeds indoors (spring) | Mar 11 – Apr 8 |
| Cabbage | Transplant outdoors (spring) | Apr 8 – May 9 |
| Cabbage | Start seeds indoors (fall) | May 23 – Jun 22 |
| Cabbage | Transplant outdoors (fall) | Jun 22 – Jul 23 |
| Leaf lettuce | Sow outdoors (spring) | Apr 8 – Jun 24 |
| Leaf lettuce | Sow outdoors (fall) | Jun 22 – Aug 8 |
| Spinach | Sow outdoors (spring) | Apr 1 – May 15 |
| Spinach | Sow outdoors (fall) | Jul 9 – Aug 13 |
| Radishes | Sow outdoors (spring) | Apr 8 – May 29 |
| Radishes | Sow outdoors (fall) | Jun 22 – Aug 23 |
| Kale | Sow outdoors (spring) | Apr 25 – May 15 |
| Kale | Sow outdoors (fall) | Jun 15 – Jul 23 |
| Carrots | Sow outdoors (spring) | May 9 – Jun 24 |
| Carrots | Sow outdoors (fall) | May 23 – Jul 8 |
| Garlic | Plant outdoors (fall) | Sep 22 – Oct 23 |
Where these dates come from
ZIP code 80134 is matched to the NOAA station Castle Rock, CO, 10.2 km away, at 6,185 ft elevation (131 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Castle Rock, CO (used) | 6,185 ft | May 9 | Oct 2 |
| Parker, CO | 5,904 ft | May 9 | Oct 3 |
| Denver Centennial Ap, CO | 5,883 ft | May 5 | Oct 8 |
| Cherry Creek Dam, CO | 5,647 ft | May 7 | Oct 8 |
Frost dates near Parker
- Castle Rock, CO 80108 · last May 9, first Oct 2
- Lone Tree, CO 80124 · last May 5, first Oct 8
- Littleton, CO 80130 · last May 5, first Oct 8
- Parker, CO 80138 · last May 9, first Oct 3
- Englewood, CO 80112 · last May 5, first Oct 8
- Louviers, CO 80131 · last May 8, first Oct 3
- Aurora, CO 80016 · last May 9, first Oct 3
- Franktown, CO 80116 · last May 9, first Oct 2
Frequently asked questions
- When is the last frost in Parker, CO?
- For ZIP code 80134, the average last spring frost (32°F) is May 9, based on NOAA 1991-2020 climate normals for the Castle Rock, CO weather station. There is a 1-in-10 chance of a frost after May 24.
- When is the first frost in Parker, CO?
- The average first fall frost (32°F) is October 2. There is a 1-in-10 chance of frost by September 17, so tender plants are at risk from that point on.
- How long is the growing season in 80134?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 143 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.