Frost dates for 80818Genoa, CO
The average last spring frost in Genoa is May 8 and the average first fall frost is October 10, giving a typical growing season of about 155 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 8
- Average first fall frost
- Oct 10
- Growing season
- 155 days
Safer after May 22 (1-in-10 risk)
Possible by Sep 28 (1-in-10 risk)
Last frost typically in 193 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 4 · May 17 · May 31 | Sep 19 · Oct 2 · Oct 14 | 137 days | 100% |
| Frost / freeze (32°F) | Apr 25 · May 8 · May 22 | Sep 28 · Oct 10 · Oct 23 | 155 days | 100% |
| Hard freeze (28°F) | Apr 12 · Apr 28 · May 11 | Oct 6 · Oct 20 · Nov 2 | 174 days | 100% |
Planting calendar for Genoa
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 20 |
| 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 30 |
| Summer squash | Sow outdoors | May 24 – Jul 8 |
| Winter squash & pumpkins | Sow outdoors | Jun 7 – Jul 8 |
| Snap beans | Sow outdoors | May 24 – Jul 23 |
| Sweet corn | Sow outdoors | May 24 – Jun 20 |
| 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 10 – Jun 20 |
| Broccoli | Transplant outdoors (fall) | Jul 10 – Jul 21 |
| Cabbage | Start seeds indoors (spring) | Mar 10 – Apr 7 |
| Cabbage | Transplant outdoors (spring) | Apr 7 – May 8 |
| Cabbage | Start seeds indoors (fall) | May 31 – Jun 30 |
| Cabbage | Transplant outdoors (fall) | Jun 30 – Jul 31 |
| Leaf lettuce | Sow outdoors (spring) | Apr 7 – Jun 23 |
| Leaf lettuce | Sow outdoors (fall) | Jun 30 – Aug 16 |
| Spinach | Sow outdoors (spring) | Mar 31 – May 14 |
| Spinach | Sow outdoors (fall) | Jul 17 – Aug 21 |
| Radishes | Sow outdoors (spring) | Apr 7 – May 28 |
| Radishes | Sow outdoors (fall) | Jun 30 – Aug 31 |
| Kale | Sow outdoors (spring) | Apr 24 – May 14 |
| Kale | Sow outdoors (fall) | Jun 23 – Jul 31 |
| Carrots | Sow outdoors (spring) | May 8 – Jun 23 |
| Carrots | Sow outdoors (fall) | May 31 – Jul 16 |
| Garlic | Plant outdoors (fall) | Sep 30 – Oct 31 |
Where these dates come from
ZIP code 80818 is matched to the NOAA station Genoa, CO, 7.4 km away, at 5,593 ft elevation (140 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Genoa, CO (used) | 5,593 ft | May 8 | Oct 10 |
| Hugo 1 Nw, CO | 5,025 ft | May 10 | Oct 2 |
| Limon Wsmo, CO | 5,364 ft | May 21 | Sep 26 |
| Shaw 4Ene, CO | 5,000 ft | May 12 | Oct 4 |
Frost dates near Genoa
- Arriba, CO 80804 · last May 5, first Oct 8
- Limon, CO 80828 · last May 21, first Sep 26
- Hugo, CO 80821 · last May 10, first Oct 2
- Flagler, CO 80815 · last May 5, first Oct 8
- Usaf Academy, CO 80840 · last May 12, first Oct 2
- Matheson, CO 80830 · last May 12, first Oct 2
- Agate, CO 80101 · last May 21, first Sep 26
- Anton, CO 80801 · last May 12, first Oct 4
Frequently asked questions
- When is the last frost in Genoa, CO?
- For ZIP code 80818, the average last spring frost (32°F) is May 8, based on NOAA 1991-2020 climate normals for the Genoa, CO weather station. There is a 1-in-10 chance of a frost after May 22.
- When is the first frost in Genoa, CO?
- The average first fall frost (32°F) is October 10. There is a 1-in-10 chance of frost by September 28, so tender plants are at risk from that point on.
- How long is the growing season in 80818?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 155 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.