USDA Hardiness Zone 5b
Frost Dates for 80537 — Loveland, Colorado
NOAA 1991–2020 normals from Loveland 2N, CO (5,080 ft), 4 miles north.
Updated
In Loveland, the last spring frost (32°F) is around May 10 in half of years and has passed by May 22 in nine years out of ten. The first fall frost comes around October 1, as early as September 15 one year in ten, leaving a typical freeze-free season of 142 days (NOAA, Loveland 2N, CO).
- Last spring frost
- May 10
- First fall frost
- October 1
- Growing season
- 142 days
- Hardiness zone
- 5b
50% probability
50% probability
freeze-free, 50%
-15 to -10°F (-26.1 to -23.3°C) coldest night
- First snow
- October 30
- Last snow
- April 18
- Winters with snow
- 100%
- Snow per year
- 47"
median, 1991–2020
median, 1991–2020
28 of 28 observed
NOAA normal
Frost risk by date in Loveland
Half of springs at Loveland 2N, CO see their last 32°F night by May 10; only one in ten is past it by April 30, and one in ten still has one after May 22. Planting tender crops after May 15 leaves a 30% risk of a frost on them, after May 18 20%, and after May 22 10%. The 12 days between the even-odds date and the one-in-ten date is narrower than at 81% of the 110 Colorado stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 1 in half of years, as early as September 15 one year in ten, and holds off past October 13 one year in ten. A hard freeze of 28°F follows 9 days later, around October 10; in spring the one-in-ten date for 28°F is May 14, 8 days before the 32°F one. The freeze-free season lasts 142 days in a typical year, shorter than at 50% of the 110 Colorado stations; it reaches 157 days one year in ten and falls short of 124 one year in ten. On average 174 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 12 days longer, to about May 22, and return around September 22. Severe cold of 16°F or below comes every winter, usually between November 5 and March 29.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 11 | May 14 | May 17 | May 19 | May 22 | May 25 | May 28 | May 31 | Jun 4 |
| 32°F | Apr 30 | May 3 | May 6 | May 8 | May 10 | May 13 | May 15 | May 18 | May 22 |
| 28°F | Apr 17 | Apr 23 | Apr 27 | Apr 30 | May 2 | May 4 | May 7 | May 10 | May 14 |
| 24°F | Apr 5 | Apr 9 | Apr 13 | Apr 16 | Apr 20 | Apr 24 | Apr 27 | May 1 | May 6 |
| 20°F | Mar 24 | Mar 30 | Apr 2 | Apr 4 | Apr 8 | Apr 11 | Apr 16 | Apr 22 | Apr 28 |
| 16°F | Mar 10 | Mar 16 | Mar 21 | Mar 25 | Mar 29 | Apr 1 | Apr 4 | Apr 8 | Apr 18 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 8 | Sep 13 | Sep 17 | Sep 20 | Sep 22 | Sep 25 | Sep 28 | Oct 1 | Oct 4 |
| 32°F | Sep 15 | Sep 21 | Sep 25 | Sep 28 | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 13 |
| 28°F | Sep 22 | Sep 29 | Oct 3 | Oct 7 | Oct 10 | Oct 12 | Oct 15 | Oct 18 | Oct 22 |
| 24°F | Oct 4 | Oct 10 | Oct 14 | Oct 17 | Oct 20 | Oct 22 | Oct 25 | Oct 29 | Nov 2 |
| 20°F | Oct 13 | Oct 19 | Oct 22 | Oct 26 | Oct 29 | Nov 1 | Nov 3 | Nov 7 | Nov 11 |
| 16°F | Oct 21 | Oct 26 | Oct 31 | Nov 3 | Nov 5 | Nov 9 | Nov 12 | Nov 16 | Nov 20 |
Freeze probabilities 1991–2020 at Loveland 2N, CO, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.
Frost risk on any date in 80537 →Compare Loveland with another place →
Weather by month in Loveland
July is the warmest month at Loveland 2N, CO, averaging 89°F by day and 55°F at night; January is the coldest at 44°F and 13°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 88% of years.
Warmth for growing adds up to 2,510 growing degree days a year (base 50°F), more than at 51% of the 110 Colorado stations. 30% of them (762) have built up by the end of June, and July adds the most, 677. Precipitation totals 15.7 inches a year, most in May (2.7") and least in January (0.5"); May to September bring 54% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 44 | 13 | 0.5 | 100% | 30 | 0 |
| Feb | 46 | 15 | 0.6 | 100% | 27 | 1 |
| Mar | 56 | 23 | 1.3 | 100% | 26 | 14 |
| Apr | 62 | 31 | 2.2 | 100% | 16 | 56 |
| May | 71 | 40 | 2.7 | 88% | 3 | 211 |
| Jun | 83 | 49 | 1.6 | 2% | 0 | 479 |
| Jul | 89 | 55 | 1.5 | 0% | 0 | 677 |
| Aug | 87 | 53 | 1.3 | 0% | 0 | 614 |
| Sep | 79 | 44 | 1.4 | 47% | 1 | 358 |
| Oct | 65 | 32 | 1.2 | 100% | 13 | 91 |
| Nov | 53 | 21 | 0.8 | 100% | 27 | 8 |
| Dec | 44 | 13 | 0.6 | 100% | 31 | 1 |
Monthly normals 1991–2020 at Loveland 2N, CO (5,080 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.
Compared with the next station
The nearest other station, Fort Collins, CO, 13 miles north of Loveland, has a last frost 8 days earlier (May 2), a first frost 6 days later (October 7), a season 15 days longer.
When it snows in Loveland, Colorado
The first measurable snow (0.1 inch or more) in Loveland usually arrives around October 30, and the last of the season around April 18. Those are the middle dates across the winters of 1991–2020 at Loveland 2N, CO, 3.7 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 22 days after the last snow.
Planting calendar for 80537
| When | What to do |
|---|---|
| March 1 – March 15 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 15 – March 29 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 12 – April 26 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 10 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 9 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 17 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 1 onward | Plant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter. |
The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.
Where these figures come from
ZIP 80537 is 4 miles from Loveland 2N, CO, which stands at 5,080 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 80538 (Loveland). The 2023 USDA Plant Hardiness Zone Map lists ZIP 80537 in zone 5b, the band where the coldest night of the year averaged -15 to -10°F (-26.1 to -23.3°C) over 1991–2020; a zone describes winter lows, not frost dates.
Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.
Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.