Loveland, Colorado: planting zone & frost dates
Loveland is in USDA plant hardiness zone 5b, where the average coldest winter night reaches -15 to -10°F (-26.1 to -23.3°C). The typical last spring frost is around May 15 and the first fall frost around Sep 25.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | May 22 | Sep 15 |
| Typical planning date (30% risk) | May 15 | Sep 25 |
| Median (50%) | May 10 | Oct 1 |
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 LOVELAND 2N, CO (USC00055236), 1.7 mi (2.7 km) from the city center and 79 ft higher than the city center (+24 m). Record used for the 1991–2020 normals: 25 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Loveland
All 3 ZIP codes covering Loveland are in zone 5b.
Vegetable planting calendar for Loveland
Dates are counted from the 30%-risk frost dates above (last frost May 15, first frost Sep 25). 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 20 – Apr 3 | May 22 – Jun 5 | — | — |
| Pepper | Mar 6 – Mar 20 | May 29 – Jun 12 | — | — |
| Lettuce | Apr 3 – Apr 17 | May 1 – May 22 | Apr 17 – May 29 | Jul 17 – Aug 14 |
| Green Beans | — | — | May 22 – Jun 26 | Jul 3 – Jul 17 |
| Sweet Corn | — | — | May 22 – Jun 19 | — |
| Zucchini & Summer Squash | Apr 17 – Apr 24 | May 22 – Jun 5 | May 22 – Jun 12 | Jul 3 – Jul 17 |
| Cucumber | Apr 17 – Apr 24 | May 29 – Jun 5 | May 22 – Jun 12 | Jul 3 – Jul 17 |
| Carrot | — | — | Apr 24 – May 29 | Jul 3 – Jul 17 |
| Onion | Feb 20 – Mar 6 | Apr 17 – May 1 | — | — |
| Potato | — | Apr 17 – May 8 | — | — |
| Basil | Apr 3 – Apr 17 | May 29 – Jun 12 | May 29 – Jun 19 | — |
| Spinach | — | — | Apr 3 – May 1 | Jul 31 – Aug 28 |
| Kale | Mar 20 – Apr 3 | Apr 17 – May 8 | Apr 17 – May 8 | Jul 17 – Aug 14 |
| Broccoli | Mar 20 – Apr 3 | May 1 – May 22 | — | Jul 3 – Jul 17 |
| Peas | — | — | Apr 3 – Apr 24 | Jul 17 – Jul 31 |
| Eggplant | Mar 6 – Mar 20 | May 29 – Jun 12 | — | — |
| Cabbage | Mar 20 – Apr 3 | Apr 17 – May 1 | — | Jul 3 – Jul 17 |
| Radish | — | — | Apr 10 – May 29 | Aug 14 – Sep 11 |
| Strawberry | — | Apr 17 – May 8 | — | — |
| Beets | — | — | Apr 24 – Jun 5 | Jul 17 – Jul 31 |
Nearby cities in Colorado
- Fort Collins — zone 5b, last frost May 7, first frost Oct 2
- Longmont — zone 5b, last frost May 13, first frost Oct 1
- Greeley — zone 5b, last frost May 7, first frost Oct 3
- Boulder — zone 6a, last frost May 11, first frost Sep 30
- Broomfield — zone 6a, last frost May 7, first frost Oct 4
- Thornton — zone 6a, last frost May 7, first frost Oct 4
More: all Colorado cities · other zone 5b cities: Madison, WI, Des Moines, IA, Aurora, IL, Fort Collins, CO, Naperville, IL, Rockford, IL, Elgin, IL, Greeley, CO
Loveland gardening questions
When is the last frost in Loveland, CO?
Plan around May 15. At NOAA's Loveland 2N, CO station, 1.7 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 May 10, and after May 22 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around May 2. The last frost is fairly predictable here: only 22 days separate the 90% and 10% dates (median for cities on this site: 36 days).
When should I plant tomatoes in Loveland, CO?
Start seeds indoors Mar 20 – Apr 3 and set transplants outside May 22 – Jun 5, once nights stay above 50°F and the soil is near 60°F. That leaves 133 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 Loveland?
About 142 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 124 days, and in 1 year in 10 it runs 157 days or more. In fall there is a 10% chance of frost by Sep 15 and a 30% chance by Sep 25. That is the shortest of the 16 Colorado cities on this site.
When should I plant a fall garden in Loveland?
Count back from the first fall frost (Sep 25): transplant broccoli Jul 3 – Jul 17; sow kale Jul 17 – Aug 14; sow lettuce Jul 17 – Aug 14; sow radishes Aug 14 – Sep 11. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Oct 10. How the math works: succession and fall planting.
Did Loveland's hardiness zone change on the 2023 map?
No. Going by the zone that covers most of the city's land, Loveland is zone 5b on both the 2012 and the 2023 USDA maps (PRISM/OSU ZIP listings). About 42% of U.S. ZIP codes kept their half-zone in 2023. Why the 2023 map is warmer.
How does Loveland compare with Fort Collins, CO?
Both are in zone 5b. The typical last spring frost in Loveland (May 15) comes about 8 days later than in Fort Collins, CO (May 7), 9 miles away, and the first fall frost is Sep 25 versus Oct 2. The two cities use different NOAA stations.