Frost dates for 80830Matheson, CO
The average last spring frost in Matheson is May 12 and the average first fall frost is October 2, giving a typical growing season of about 141 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 12
- Average first fall frost
- Oct 2
- Growing season
- 141 days
Safer after May 26 (1-in-10 risk)
Possible by Sep 19 (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 11 · May 22 · Jun 4 | Sep 12 · Sep 24 · Oct 5 | 123 days | 100% |
| Frost / freeze (32°F) | May 1 · May 12 · May 26 | Sep 19 · Oct 2 · Oct 14 | 141 days | 100% |
| Hard freeze (28°F) | Apr 20 · May 2 · May 15 | Sep 27 · Oct 11 · Oct 23 | 161 days | 100% |
Planting calendar for Matheson
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 11 – Jun 17 |
| Tomatoes | Transplant outdoors | May 28 – Jun 12 |
| Peppers | Start seeds indoors | Apr 11 – May 12 |
| Peppers | Transplant outdoors | Jun 11 – Jul 12 |
| Eggplant | Start seeds indoors | Apr 28 – May 27 |
| Eggplant | Transplant outdoors | Jun 11 – Jul 12 |
| Cucumbers | Sow outdoors | Jun 11 – Jun 22 |
| Summer squash | Sow outdoors | May 28 – Jul 12 |
| Winter squash & pumpkins | Sow outdoors | Jun 11 – Jul 12 |
| Snap beans | Sow outdoors | May 28 – Jul 15 |
| Sweet corn | Sow outdoors | May 28 – Jun 12 |
| Watermelon & cantaloupe | Sow outdoors | Jun 11 – Jul 12 |
| Okra | Sow outdoors | Jun 4 – Jun 27 |
| Peas | Sow outdoors (spring) | Apr 11 – May 27 |
| Potatoes | Plant outdoors (spring) | Apr 11 – Jun 11 |
| Onions | Start seeds indoors (spring) | Feb 28 – Mar 27 |
| Onions | Transplant outdoors (spring) | Apr 28 – May 27 |
| Broccoli | Start seeds indoors (spring) | Mar 24 – Apr 27 |
| Broccoli | Transplant outdoors (spring) | Apr 28 – May 27 |
| Broccoli | Start seeds indoors (fall) | Jun 2 – Jun 12 |
| Broccoli | Transplant outdoors (fall) | Jul 2 – Jul 13 |
| Cabbage | Start seeds indoors (spring) | Mar 14 – Apr 11 |
| Cabbage | Transplant outdoors (spring) | Apr 11 – May 12 |
| Cabbage | Start seeds indoors (fall) | May 23 – Jun 22 |
| Cabbage | Transplant outdoors (fall) | Jun 22 – Jul 23 |
| Leaf lettuce | Sow outdoors (spring) | Apr 11 – Jun 27 |
| Leaf lettuce | Sow outdoors (fall) | Jun 22 – Aug 8 |
| Spinach | Sow outdoors (spring) | Apr 4 – May 18 |
| Spinach | Sow outdoors (fall) | Jul 9 – Aug 13 |
| Radishes | Sow outdoors (spring) | Apr 11 – Jun 1 |
| Radishes | Sow outdoors (fall) | Jun 22 – Aug 23 |
| Kale | Sow outdoors (spring) | Apr 28 – May 18 |
| Kale | Sow outdoors (fall) | Jun 15 – Jul 23 |
| Carrots | Sow outdoors (spring) | May 12 – Jun 27 |
| Carrots | Sow outdoors (fall) | May 23 – Jul 8 |
| Garlic | Plant outdoors (fall) | Sep 22 – Oct 23 |
Where these dates come from
ZIP code 80830 is matched to the NOAA station Matheson 8 Se, CO, 5.8 km away, at 5,830 ft elevation (203 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Matheson 8 Se, CO (used) | 5,830 ft | May 12 | Oct 2 |
| Limon Wsmo, CO | 5,364 ft | May 21 | Sep 26 |
| Rush 1N, CO | 6,054 ft | May 9 | Oct 4 |
| Hugo 1 Nw, CO | 5,025 ft | May 10 | Oct 2 |
Frost dates near Matheson
- Usaf Academy, CO 80840 · last May 12, first Oct 2
- Simla, CO 80835 · last May 12, first Oct 2
- Ramah, CO 80832 · last May 16, first Oct 2
- Limon, CO 80826 · last May 21, first Sep 26
- Agate, CO 80101 · last May 21, first Sep 26
- Hugo, CO 80821 · last May 10, first Oct 2
- Rush, CO 80833 · last May 9, first Oct 4
- Calhan, CO 80808 · last May 3, first Oct 8
Frequently asked questions
- When is the last frost in Matheson, CO?
- For ZIP code 80830, the average last spring frost (32°F) is May 12, based on NOAA 1991-2020 climate normals for the Matheson 8 Se, CO weather station. There is a 1-in-10 chance of a frost after May 26.
- When is the first frost in Matheson, CO?
- The average first fall frost (32°F) is October 2. There is a 1-in-10 chance of frost by September 19, so tender plants are at risk from that point on.
- How long is the growing season in 80830?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 141 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.