Pueblo, Colorado: planting zone & frost dates
Pueblo is in USDA plant hardiness zone 6a, where the average coldest winter night reaches -10 to -5°F (-23.3 to -20.6°C). The typical last spring frost is around May 4 and the first fall frost around Oct 4.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | May 12 | Sep 27 |
| Typical planning date (30% risk) | May 4 | Oct 4 |
| Median (50%) | Apr 30 | Oct 9 |
How to read this: after the spring "10% risk" date, a 32°F frost happens in only about 1 year in 10. In fall, the "10% risk" date is the early end — a frost before it happens about 1 year in 10.
Frost data comes from NOAA station PUEBLO MEM AP, CO (USW00093058), 6.3 mi (10.1 km) from the city center and 56 ft higher than the city center (+17 m). Record used for the 1991–2020 normals: 29 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Pueblo
All 6 ZIP codes covering Pueblo are in zone 6a.
Vegetable planting calendar for Pueblo
Dates are counted from the 30%-risk frost dates above (last frost May 4, first frost Oct 4). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Mar 9 – Mar 23 | May 11 – May 25 | — | — |
| Pepper | Feb 23 – Mar 9 | May 18 – Jun 1 | — | — |
| Lettuce | Mar 23 – Apr 6 | Apr 20 – May 11 | Apr 6 – May 18 | Jul 26 – Aug 23 |
| Green Beans | — | — | May 11 – Jun 15 | Jul 12 – Jul 26 |
| Sweet Corn | — | — | May 11 – Jun 8 | — |
| Zucchini & Summer Squash | Apr 6 – Apr 13 | May 11 – May 25 | May 11 – Jun 1 | Jul 12 – Jul 26 |
| Cucumber | Apr 6 – Apr 13 | May 18 – May 25 | May 11 – Jun 1 | Jul 12 – Jul 26 |
| Carrot | — | — | Apr 13 – May 18 | Jul 12 – Jul 26 |
| Onion | Feb 9 – Feb 23 | Apr 6 – Apr 20 | — | — |
| Potato | — | Apr 6 – Apr 27 | — | — |
| Basil | Mar 23 – Apr 6 | May 18 – Jun 1 | May 18 – Jun 8 | — |
| Spinach | — | — | Mar 23 – Apr 20 | Aug 9 – Sep 6 |
| Kale | Mar 9 – Mar 23 | Apr 6 – Apr 27 | Apr 6 – Apr 27 | Jul 26 – Aug 23 |
| Broccoli | Mar 9 – Mar 23 | Apr 20 – May 11 | — | Jul 12 – Jul 26 |
| Peas | — | — | Mar 23 – Apr 13 | Jul 26 – Aug 9 |
| Eggplant | Feb 23 – Mar 9 | May 18 – Jun 1 | — | — |
| Cabbage | Mar 9 – Mar 23 | Apr 6 – Apr 20 | — | Jul 12 – Jul 26 |
| Radish | — | — | Mar 30 – May 18 | Aug 23 – Sep 20 |
| Strawberry | — | Apr 6 – Apr 27 | — | — |
| Beets | — | — | Apr 13 – May 25 | Jul 26 – Aug 9 |
Nearby cities in Colorado
- Colorado Springs — zone 6a, last frost May 8, first frost Oct 3
- Castle Rock — zone 5b, last frost May 15, first frost Sep 27
- Centennial — zone 6a, last frost May 10, first frost Oct 3
- Aurora — zone 6a, last frost May 12, first frost Oct 2
- Lakewood — zone 6a, last frost May 8, first frost Oct 2
- Denver — zone 6a, last frost May 8, first frost Oct 3
More: all Colorado cities · other zone 6a cities: Chicago, IL, Denver, CO, Milwaukee, WI, Colorado Springs, CO, Omaha, NE, Aurora, CO, Lincoln, NE, Fort Wayne, IN
Pueblo gardening questions
When is the last frost in Pueblo, CO?
Plan around May 4. At NOAA's Pueblo Mem Airport, CO station, 6.3 mi from the city center, there is a 30% chance of a 32°F frost after that date. Half of springs have their last frost by Apr 30, and after May 12 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Apr 19. The last frost is fairly predictable here: only 24 days separate the 90% and 10% dates (median for cities on this site: 36 days).
When should I plant tomatoes in Pueblo, CO?
Start seeds indoors Mar 9 – Mar 23 and set transplants outside May 11 – May 25, once nights stay above 50°F and the soil is near 60°F. That leaves 153 days between the 30% frost dates, enough for most varieties including 80–85-day slicers. More: tomato planting dates by zone.
How long is the growing season in Pueblo?
About 161 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 144 days, and in 1 year in 10 it runs 179 days or more. In fall there is a 10% chance of frost by Sep 27 and a 30% chance by Oct 4. That is the longest of the 16 Colorado cities on this site.
When should I plant a fall garden in Pueblo?
Count back from the first fall frost (Oct 4): transplant broccoli Jul 12 – Jul 26; sow kale Jul 26 – Aug 23; sow lettuce Jul 26 – Aug 23; sow radishes Aug 23 – Sep 20. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Oct 18. How the math works: succession and fall planting.
Did Pueblo's hardiness zone change on the 2023 map?
Yes. Most of Pueblo was zone 5b on the 2012 map and is zone 6a on the 2023 map — half a zone warmer, like about 56% of U.S. ZIP codes. The shift comes from a newer 1991–2020 averaging period plus more weather stations and better mapping; it does not mean last frost comes earlier. Why the 2023 map is warmer.
How does Pueblo compare with Colorado Springs, CO?
Both are in zone 6a. The typical last spring frost in Pueblo (May 4) comes about 4 days earlier than in Colorado Springs, CO (May 8), 42 miles away, and the first fall frost is Oct 4 versus Oct 3. Pueblo sits about 1,674 ft lower, which explains part of the gap. The two cities use different NOAA stations.