USDA Hardiness Zone 5b
Frost Dates for 81132 — Del Norte, Colorado
NOAA 1991–2020 normals from Del Norte 3ENE, CO (7,845 ft), 6 miles southeast.
Updated
In Del Norte, the last spring frost (32°F) is around May 23 in half of years and has passed by June 8 in nine years out of ten. The first fall frost comes around September 25, as early as September 13 one year in ten, leaving a typical freeze-free season of 123 days (NOAA, Del Norte 3ENE, CO).
- Last spring frost
- May 23
- First fall frost
- September 25
- Growing season
- 123 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 29
- Winters with snow
- 100%
- Snow per year
- 38.6"
median, 1991–2020
median, 1991–2020
30 of 30 observed
NOAA normal
Frost risk by date in Del Norte
Half of springs at Del Norte 3ENE, CO see their last 32°F night by May 23; only one in ten is past it by May 11, and one in ten still has one after June 8. Planting tender crops after May 31 leaves a 30% risk of a frost on them, after June 3 20%, and after June 8 10%. The 16 days between the even-odds date and the one-in-ten date is wider than at 75% of the 110 Colorado stations behind this site's ZIP pages.
In fall the first 32°F night comes by September 25 in half of years, as early as September 13 one year in ten, and holds off past October 7 one year in ten. A hard freeze of 28°F follows 9 days later, around October 4; in spring the one-in-ten date for 28°F is May 26, 13 days before the 32°F one. The freeze-free season lasts 123 days in a typical year, shorter than at 65% of the 110 Colorado stations; it reaches 141 days one year in ten and falls short of 103 one year in ten. On average 213 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 14 days longer, to about June 6, and return around September 17. Severe cold of 16°F or below comes every winter, usually between November 2 and April 5.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 24 | May 29 | Jun 2 | Jun 4 | Jun 6 | Jun 8 | Jun 12 | Jun 15 | Jun 19 |
| 32°F | May 11 | May 15 | May 18 | May 21 | May 23 | May 26 | May 31 | Jun 3 | Jun 8 |
| 28°F | Apr 28 | May 2 | May 4 | May 7 | May 9 | May 12 | May 15 | May 19 | May 26 |
| 24°F | Apr 15 | Apr 20 | Apr 22 | Apr 26 | Apr 28 | May 1 | May 3 | May 6 | May 12 |
| 20°F | Apr 3 | Apr 7 | Apr 11 | Apr 14 | Apr 16 | Apr 19 | Apr 22 | Apr 25 | Apr 30 |
| 16°F | Mar 16 | Mar 25 | Mar 31 | Apr 2 | Apr 5 | Apr 8 | Apr 11 | Apr 15 | Apr 20 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 6 | Sep 10 | Sep 13 | Sep 15 | Sep 17 | Sep 19 | Sep 21 | Sep 23 | Sep 26 |
| 32°F | Sep 13 | Sep 18 | Sep 21 | Sep 23 | Sep 25 | Sep 27 | Sep 30 | Oct 3 | Oct 7 |
| 28°F | Sep 21 | Sep 25 | Sep 29 | Oct 1 | Oct 4 | Oct 6 | Oct 9 | Oct 13 | Oct 17 |
| 24°F | Sep 29 | Oct 3 | Oct 6 | Oct 9 | Oct 13 | Oct 15 | Oct 18 | Oct 21 | Oct 26 |
| 20°F | Oct 9 | Oct 14 | Oct 18 | Oct 20 | Oct 23 | Oct 26 | Oct 30 | Nov 1 | Nov 5 |
| 16°F | Oct 19 | Oct 23 | Oct 27 | Oct 31 | Nov 2 | Nov 5 | Nov 8 | Nov 11 | Nov 15 |
Freeze probabilities 1991–2020 at Del Norte 3ENE, 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 81132 →Compare Del Norte with another place →
Weather by month in Del Norte
July is the warmest month at Del Norte 3ENE, CO, averaging 81°F by day and 50°F at night; January is the coldest at 35°F and 7°F. A freezing night is all but certain in every month from October to May (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, June still brings one in 28% of years.
Warmth for growing adds up to 1,586 growing degree days a year (base 50°F), fewer than at 73% of the 110 Colorado stations. 29% of them (454) have built up by the end of June, and July adds the most, 467. Precipitation totals 9.8 inches a year, most in August (1.7") and least in January (0.4"); May to September bring 58% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 35 | 7 | 0.4 | 100% | 31 | 0 |
| Feb | 40 | 13 | 0.4 | 100% | 28 | 0 |
| Mar | 52 | 21 | 0.7 | 100% | 30 | 1 |
| Apr | 59 | 27 | 0.8 | 100% | 26 | 15 |
| May | 68 | 36 | 0.8 | 99% | 10 | 118 |
| Jun | 78 | 44 | 0.6 | 28% | 1 | 320 |
| Jul | 81 | 50 | 1.5 | 0% | 0 | 467 |
| Aug | 79 | 49 | 1.7 | 0% | 0 | 419 |
| Sep | 73 | 40 | 1.1 | 72% | 4 | 211 |
| Oct | 63 | 30 | 0.8 | 100% | 22 | 36 |
| Nov | 49 | 18 | 0.5 | 100% | 30 | 0 |
| Dec | 36 | 9 | 0.5 | 100% | 31 | 0 |
Monthly normals 1991–2020 at Del Norte 3ENE, CO (7,845 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, Center 4 SSW, CO, 14 miles east of Del Norte and 172 feet lower, has a last frost 1 day later (May 24), a first frost 1 day earlier (September 24), a season 3 days shorter.
When it snows in Del Norte, Colorado
The first measurable snow (0.1 inch or more) in Del Norte usually arrives around October 30, and the last of the season around April 29. Those are the middle dates across the winters of 1991–2020 at Del Norte 3ENE, CO, 5.7 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 24 days after the last snow.
Planting calendar for 81132
| When | What to do |
|---|---|
| March 14 – March 28 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 28 – April 11 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 25 – May 9 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 23 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 3 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 11 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| September 25 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 81132 is 6 miles from Del Norte 3ENE, CO, which stands at 7,845 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 81132 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.