USDA Hardiness Zone 5b
Frost Dates for 80442 — Fraser, Colorado
NOAA 1991–2020 normals from Grand Lake 6 SSW, CO (8,288 ft), 16 miles north.
Updated
In Fraser, the last spring frost (32°F) is around June 13 in half of years and has passed by June 28 in nine years out of ten. The first fall frost comes around September 7, as early as August 21 one year in ten, leaving a typical freeze-free season of 84 days (NOAA, Grand Lake 6 SSW, CO).
- Last spring frost
- June 13
- First fall frost
- September 7
- Growing season
- 84 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 4
- Last snow
- May 9
- Winters with snow
- 100%
- Snow per year
- 143.2"
median, 1991–2020
median, 1991–2020
29 of 29 observed
NOAA normal
Frost risk by date in Fraser
Half of springs at Grand Lake 6 SSW, CO see their last 32°F night by June 13; only one in ten is past it by June 1, and one in ten still has one after June 28. Planting tender crops after June 19 leaves a 30% risk of a frost on them, after June 23 20%, and after June 28 10%. The 15 days between the even-odds date and the one-in-ten date is wider than at 56% of the 110 Colorado stations behind this site's ZIP pages.
In fall the first 32°F night comes by September 7 in half of years, as early as August 21 one year in ten, and holds off past September 21 one year in ten. A hard freeze of 28°F follows 15 days later, around September 22; in spring the one-in-ten date for 28°F is June 10, 18 days before the 32°F one. The freeze-free season lasts 84 days in a typical year, shorter than at 94% of the 110 Colorado stations; it reaches 103 days one year in ten and falls short of 61 one year in ten. On average 245 nights a year drop to 32°F or below. Severe cold of 16°F or below comes every winter, usually between October 26 and April 20.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | too rare for a date | ||||||||
| 32°F | Jun 1 | Jun 5 | Jun 8 | Jun 10 | Jun 13 | Jun 17 | Jun 19 | Jun 23 | Jun 28 |
| 28°F | May 12 | May 17 | May 20 | May 23 | May 26 | May 30 | Jun 2 | Jun 5 | Jun 10 |
| 24°F | Apr 29 | May 2 | May 5 | May 7 | May 10 | May 12 | May 15 | May 18 | May 23 |
| 20°F | Apr 16 | Apr 21 | Apr 24 | Apr 27 | Apr 30 | May 2 | May 5 | May 9 | May 14 |
| 16°F | Apr 5 | Apr 10 | Apr 13 | Apr 15 | Apr 20 | Apr 23 | Apr 27 | May 1 | May 4 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | too rare for a date | ||||||||
| 32°F | Aug 21 | Aug 29 | Sep 2 | Sep 5 | Sep 7 | Sep 10 | Sep 13 | Sep 16 | Sep 21 |
| 28°F | Sep 8 | Sep 13 | Sep 16 | Sep 19 | Sep 22 | Sep 24 | Sep 27 | Oct 1 | Oct 4 |
| 24°F | Sep 22 | Sep 26 | Sep 30 | Oct 2 | Oct 5 | Oct 7 | Oct 10 | Oct 13 | Oct 18 |
| 20°F | Oct 3 | Oct 7 | Oct 10 | Oct 14 | Oct 17 | Oct 19 | Oct 21 | Oct 25 | Oct 30 |
| 16°F | Oct 11 | Oct 16 | Oct 19 | Oct 22 | Oct 26 | Oct 28 | Oct 31 | Nov 3 | Nov 7 |
Freeze probabilities 1991–2020 at Grand Lake 6 SSW, 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 80442 →Compare Fraser with another place →
Weather by month in Fraser
July is the warmest month at Grand Lake 6 SSW, CO, averaging 75°F by day and 44°F at night; January is the coldest at 26°F and 3°F. A freezing night is all but certain in every month from September to May (a 90% chance or more). July is the only month with under a 10% chance of a 32°F night. In spring, June still brings one in 90% of years.
Warmth for growing adds up to 778 growing degree days a year (base 50°F), fewer than at 95% of the 110 Colorado stations. 20% of them (158) have built up by the end of June, and July adds the most, 293. Precipitation totals 13.8 inches a year, most in August (1.7") and least in March (0.7"); May to September bring 55% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 26 | 3 | 0.9 | 100% | 31 | 0 |
| Feb | 31 | 5 | 0.8 | 100% | 28 | 0 |
| Mar | 40 | 13 | 0.7 | 100% | 31 | 0 |
| Apr | 48 | 23 | 1.2 | 100% | 29 | 0 |
| May | 59 | 31 | 1.6 | 100% | 22 | 19 |
| Jun | 70 | 38 | 1.2 | 90% | 5 | 139 |
| Jul | 75 | 44 | 1.6 | 8% | <1 | 293 |
| Aug | 73 | 43 | 1.7 | 24% | 1 | 242 |
| Sep | 67 | 36 | 1.5 | 98% | 12 | 81 |
| Oct | 55 | 27 | 1.1 | 100% | 26 | 3 |
| Nov | 40 | 18 | 0.7 | 100% | 29 | 0 |
| Dec | 28 | 8 | 0.8 | 100% | 31 | 0 |
Monthly normals 1991–2020 at Grand Lake 6 SSW, CO (8,288 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, Boulder 14 W, CO, 17 miles east of Fraser and 1,540 feet higher, has a last frost 8 days later (June 21), a first frost 5 days earlier (September 2), a season 13 days shorter.
When it snows in Fraser, Colorado
The first measurable snow (0.1 inch or more) in Fraser usually arrives around October 4, and the last of the season around May 9. Those are the middle dates across the winters of 1991–2020 at Fraser, CO, 1 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 35 days after the last snow.
Planting calendar for 80442
| When | What to do |
|---|---|
| April 4 – April 18 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| April 18 – May 2 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| May 16 – May 30 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| June 13 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by June 15 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by August 24 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| September 7 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 80442 is 16 miles from Grand Lake 6 SSW, CO, which stands at 8,288 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station; its figures are presented in full for 80446 (Granby). The 2023 USDA Plant Hardiness Zone Map lists ZIP 80442 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.