USDA Hardiness Zone 6b
Frost Dates for 73942 — Guymon, Oklahoma
NOAA 1991–2020 normals from Guymon Municipal Airport, OK (3,123 ft), 4 miles south.
Updated
In Guymon, the last spring frost (32°F) is around April 18 in half of years and has passed by May 1 in nine years out of ten. The first fall frost comes around October 23, as early as October 11 one year in ten, leaving a typical freeze-free season of 188 days (NOAA, Guymon Municipal Airport, OK).
- Last spring frost
- April 18
- First fall frost
- October 23
- Growing season
- 188 days
- Hardiness zone
- 6b
50% probability
50% probability
freeze-free, 50%
-5 to 0°F (-20.6 to -17.8°C) coldest night
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 36%
- Snow per year
- 2.7"
median, 1991–2020
median, 1991–2020
9 of 25 observed
NOAA normal
Frost risk by date in Guymon
Half of springs at Guymon Municipal Airport, OK see their last 32°F night by April 18; only one in ten is past it by April 4, and one in ten still has one after May 1. Planting tender crops after April 23 leaves a 30% risk of a frost on them, after April 27 20%, and after May 1 10%. The 13 days between the even-odds date and the one-in-ten date is the narrowest of the 114 Oklahoma stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 23 in half of years, as early as October 11 one year in ten, and holds off past November 3 one year in ten. A hard freeze of 28°F follows 9 days later, around November 1; in spring the one-in-ten date for 28°F is April 23, 8 days before the 32°F one. The freeze-free season lasts 188 days in a typical year, shorter than at 98% of the 114 Oklahoma stations; it reaches 205 days one year in ten and falls short of 168 one year in ten. On average 122 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 10 days longer, to about April 28, and return around October 14. Severe cold of 16°F or below comes every winter, usually between November 27 and March 3.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 14 | Apr 19 | Apr 22 | Apr 25 | Apr 28 | Apr 30 | May 2 | May 5 | May 10 |
| 32°F | Apr 4 | Apr 8 | Apr 12 | Apr 15 | Apr 18 | Apr 20 | Apr 23 | Apr 27 | May 1 |
| 28°F | Mar 23 | Mar 29 | Apr 2 | Apr 5 | Apr 8 | Apr 11 | Apr 14 | Apr 18 | Apr 23 |
| 24°F | Mar 8 | Mar 15 | Mar 21 | Mar 25 | Mar 29 | Apr 2 | Apr 4 | Apr 7 | Apr 14 |
| 20°F | Feb 26 | Mar 3 | Mar 6 | Mar 9 | Mar 13 | Mar 18 | Mar 22 | Mar 28 | Apr 3 |
| 16°F | Feb 12 | Feb 19 | Feb 24 | Feb 28 | Mar 3 | Mar 6 | Mar 9 | Mar 15 | Mar 21 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 2 | Oct 6 | Oct 9 | Oct 12 | Oct 14 | Oct 17 | Oct 19 | Oct 22 | Oct 26 |
| 32°F | Oct 11 | Oct 16 | Oct 19 | Oct 21 | Oct 23 | Oct 26 | Oct 28 | Oct 31 | Nov 3 |
| 28°F | Oct 19 | Oct 23 | Oct 27 | Oct 30 | Nov 1 | Nov 3 | Nov 5 | Nov 8 | Nov 12 |
| 24°F | Oct 27 | Oct 31 | Nov 2 | Nov 5 | Nov 8 | Nov 11 | Nov 13 | Nov 17 | Nov 22 |
| 20°F | Nov 1 | Nov 6 | Nov 11 | Nov 14 | Nov 17 | Nov 20 | Nov 24 | Nov 29 | Dec 4 |
| 16°F | Nov 9 | Nov 16 | Nov 21 | Nov 24 | Nov 27 | Dec 1 | Dec 4 | Dec 9 | Dec 15 |
Freeze probabilities 1991–2020 at Guymon Municipal Airport, OK, 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 73942 →Compare Guymon with another place →
Weather by month in Guymon
July is the warmest month at Guymon Municipal Airport, OK, averaging 95°F by day and 67°F at night; January is the coldest at 51°F and 22°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 11% of years.
Warmth for growing adds up to 4,437 growing degree days a year (base 50°F), fewer than at 97% of the 114 Oklahoma stations. 37% of them (1,620) have built up by the end of June, and July adds the most, 953. Precipitation totals 17.9 inches a year, most in June (2.9") and least in February (0.3"); May to September bring 65% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 51 | 22 | 0.4 | 100% | 28 | 6 |
| Feb | 54 | 24 | 0.3 | 100% | 24 | 21 |
| Mar | 63 | 32 | 1.1 | 100% | 16 | 86 |
| Apr | 71 | 41 | 1.5 | 94% | 5 | 224 |
| May | 81 | 51 | 2.3 | 11% | <1 | 498 |
| Jun | 91 | 62 | 2.9 | 0% | 0 | 784 |
| Jul | 95 | 67 | 2.4 | 0% | 0 | 953 |
| Aug | 92 | 65 | 2.6 | 0% | 0 | 882 |
| Sep | 85 | 57 | 1.4 | 0% | 0 | 630 |
| Oct | 73 | 43 | 1.8 | 82% | 4 | 286 |
| Nov | 61 | 31 | 0.5 | 100% | 17 | 60 |
| Dec | 50 | 23 | 0.7 | 100% | 28 | 7 |
Monthly normals 1991–2020 at Guymon Municipal Airport, OK (3,123 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, Hooker, OK, 17 miles northeast of Guymon, has a last frost 2 days earlier (April 16), a first frost 2 days later (October 25), a season 4 days longer.
When it snows in Guymon, Oklahoma
Measurable snow is rare here: only 9 of 25 winters from 1991 to 2020 recorded 0.1 inch or more at Goodwell Rsch Stn, OK, 12.5 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 73942
| When | What to do |
|---|---|
| February 7 – February 21 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 21 – March 7 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 21 – April 4 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 18 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 31 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 9 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 23 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 73942 is 4 miles from Guymon Municipal Airport, OK, which stands at 3,123 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 73942 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°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.