Frost dates for 80129Littleton, CO
The average last spring frost in Littleton is May 8 and the average first fall frost is October 3, giving a typical growing season of about 147 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 8
- Average first fall frost
- Oct 3
- Growing season
- 147 days
Safer after May 22 (1-in-10 risk)
Possible by Sep 21 (1-in-10 risk)
Last frost typically in 186 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 5 · May 19 · Jun 2 | Sep 13 · Sep 27 · Oct 8 | 128 days | 100% |
| Frost / freeze (32°F) | Apr 27 · May 8 · May 22 | Sep 21 · Oct 3 · Oct 17 | 147 days | 100% |
| Hard freeze (28°F) | Apr 15 · Apr 29 · May 13 | Sep 28 · Oct 13 · Oct 28 | 167 days | 100% |
Planting calendar for Littleton
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 7 – Jun 13 |
| Tomatoes | Transplant outdoors | May 24 – Jun 13 |
| Peppers | Start seeds indoors | Apr 7 – May 8 |
| Peppers | Transplant outdoors | Jun 7 – Jul 8 |
| Eggplant | Start seeds indoors | Apr 24 – May 23 |
| Eggplant | Transplant outdoors | Jun 7 – Jul 8 |
| Cucumbers | Sow outdoors | Jun 7 – Jun 23 |
| Summer squash | Sow outdoors | May 24 – Jul 8 |
| Winter squash & pumpkins | Sow outdoors | Jun 7 – Jul 8 |
| Snap beans | Sow outdoors | May 24 – Jul 16 |
| Sweet corn | Sow outdoors | May 24 – Jun 13 |
| Watermelon & cantaloupe | Sow outdoors | Jun 7 – Jul 8 |
| Okra | Sow outdoors | May 31 – Jun 23 |
| Peas | Sow outdoors (spring) | Apr 7 – May 23 |
| Potatoes | Plant outdoors (spring) | Apr 7 – Jun 7 |
| Onions | Start seeds indoors (spring) | Feb 24 – Mar 23 |
| Onions | Transplant outdoors (spring) | Apr 24 – May 23 |
| Broccoli | Start seeds indoors (spring) | Mar 20 – Apr 23 |
| Broccoli | Transplant outdoors (spring) | Apr 24 – May 23 |
| Broccoli | Start seeds indoors (fall) | Jun 3 – Jun 13 |
| Broccoli | Transplant outdoors (fall) | Jul 3 – Jul 14 |
| Cabbage | Start seeds indoors (spring) | Mar 10 – Apr 7 |
| Cabbage | Transplant outdoors (spring) | Apr 7 – May 8 |
| Cabbage | Start seeds indoors (fall) | May 24 – Jun 23 |
| Cabbage | Transplant outdoors (fall) | Jun 23 – Jul 24 |
| Leaf lettuce | Sow outdoors (spring) | Apr 7 – Jun 23 |
| Leaf lettuce | Sow outdoors (fall) | Jun 23 – Aug 9 |
| Spinach | Sow outdoors (spring) | Mar 31 – May 14 |
| Spinach | Sow outdoors (fall) | Jul 10 – Aug 14 |
| Radishes | Sow outdoors (spring) | Apr 7 – May 28 |
| Radishes | Sow outdoors (fall) | Jun 23 – Aug 24 |
| Kale | Sow outdoors (spring) | Apr 24 – May 14 |
| Kale | Sow outdoors (fall) | Jun 16 – Jul 24 |
| Carrots | Sow outdoors (spring) | May 8 – Jun 23 |
| Carrots | Sow outdoors (fall) | May 24 – Jul 9 |
| Garlic | Plant outdoors (fall) | Sep 23 – Oct 24 |
Where these dates come from
ZIP code 80129 is matched to the NOAA station Kassler, CO, 9.1 km away, at 5,587 ft elevation (50 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Kassler, CO (used) | 5,587 ft | May 8 | Oct 3 |
| Marston Fltr Plt, CO | 5,610 ft | May 2 | Oct 11 |
| Roxborough Sp, CO | 6,117 ft | May 16 | Oct 1 |
| Denver Centennial Ap, CO | 5,883 ft | May 5 | Oct 8 |
Frost dates near Littleton
- Littleton, CO 80126 · last May 5, first Oct 8
- Louviers, CO 80131 · last May 8, first Oct 3
- Englewood, CO 80112 · last May 5, first Oct 8
- Lone Tree, CO 80124 · last May 5, first Oct 8
- Denver, CO 80236 · last Apr 30, first Oct 12
- Parker, CO 80134 · last May 9, first Oct 2
- Morrison, CO 80465 · last May 16, first Oct 1
- Castle Rock, CO 80108 · last May 9, first Oct 2
Frequently asked questions
- When is the last frost in Littleton, CO?
- For ZIP code 80129, the average last spring frost (32°F) is May 8, based on NOAA 1991-2020 climate normals for the Kassler, CO weather station. There is a 1-in-10 chance of a frost after May 22.
- When is the first frost in Littleton, CO?
- The average first fall frost (32°F) is October 3. There is a 1-in-10 chance of frost by September 21, so tender plants are at risk from that point on.
- How long is the growing season in 80129?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 147 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.