USDA Hardiness Zone 8a
Frost Dates for 73542 — Frederick, Oklahoma
NOAA 1991–2020 normals from Altus AFB, OK (1,267 ft), 3 miles south.
Updated
In Frederick, the last spring frost (32°F) is around March 26 in half of years and has passed by April 14 in nine years out of ten. The first fall frost comes around November 10, as early as October 26 one year in ten, leaving a typical freeze-free season of 229 days (NOAA, Altus AFB, OK).
- Last spring frost
- March 26
- First fall frost
- November 10
- Growing season
- 229 days
- Hardiness zone
- 8a
50% probability
50% probability
freeze-free, 50%
10 to 15°F (-12.2 to -9.4°C) coldest night
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 48%
- Snow per year
- 0.8"
median, 1991–2020
median, 1991–2020
10 of 21 observed
NOAA normal
Frost risk by date in Frederick
Half of springs at Altus AFB, OK see their last 32°F night by March 26; only one in ten is past it by March 8, and one in ten still has one after April 14. Planting tender crops after April 3 leaves a 30% risk of a frost on them, after April 7 20%, and after April 14 10%. The 19 days between the even-odds date and the one-in-ten date is wider than at 81% of the 114 Oklahoma stations behind this site's ZIP pages.
In fall the first 32°F night comes by November 10 in half of years, as early as October 26 one year in ten, and holds off past November 27 one year in ten. A hard freeze of 28°F follows 11 days later, around November 21; in spring the one-in-ten date for 28°F is April 1, 13 days before the 32°F one. The freeze-free season lasts 229 days in a typical year, longer than at 95% of the 114 Oklahoma stations; it reaches 250 days one year in ten and falls short of 205 one year in ten. On average 64 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 13 days longer, to about April 8, and return around November 2. Nights of 24°F, cold enough to damage hardier plants, come in 100% of winters and 16°F in 82%.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Mar 22 | Mar 28 | Apr 1 | Apr 5 | Apr 8 | Apr 11 | Apr 15 | Apr 19 | Apr 24 |
| 32°F | Mar 8 | Mar 13 | Mar 18 | Mar 22 | Mar 26 | Mar 31 | Apr 3 | Apr 7 | Apr 14 |
| 28°F | Feb 23 | Mar 1 | Mar 5 | Mar 8 | Mar 11 | Mar 15 | Mar 19 | Mar 25 | Apr 1 |
| 24°F | Feb 4 | Feb 13 | Feb 19 | Feb 25 | Feb 28 | Mar 3 | Mar 7 | Mar 11 | Mar 17 |
| 20°F99% of yrs | Jan 13 | Jan 24 | Feb 1 | Feb 8 | Feb 13 | Feb 19 | Feb 25 | Mar 1 | Mar 6 |
| 16°F82% of yrs | Dec 23 | Jan 4 | Jan 14 | Jan 21 | Jan 27 | Feb 2 | Feb 9 | Feb 17 | Feb 27 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 20 | Oct 24 | Oct 28 | Oct 31 | Nov 2 | Nov 4 | Nov 7 | Nov 11 | Nov 15 |
| 32°F | Oct 26 | Oct 31 | Nov 4 | Nov 7 | Nov 10 | Nov 13 | Nov 16 | Nov 20 | Nov 27 |
| 28°F | Nov 2 | Nov 9 | Nov 13 | Nov 17 | Nov 21 | Nov 25 | Nov 29 | Dec 2 | Dec 8 |
| 24°F | Nov 12 | Nov 20 | Nov 25 | Nov 29 | Dec 2 | Dec 6 | Dec 10 | Dec 15 | Dec 22 |
| 20°F99% of yrs | Nov 23 | Dec 1 | Dec 6 | Dec 11 | Dec 17 | Dec 22 | Dec 29 | Jan 4 | Jan 13 |
| 16°F82% of yrs | Dec 3 | Dec 10 | Dec 17 | Dec 23 | Dec 29 | Jan 4 | Jan 10 | Jan 21 | Feb 2 |
Freeze probabilities 1991–2020 at Altus AFB, 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 73542 →Compare Frederick with another place →
Weather by month in Frederick
July is the warmest month at Altus AFB, OK, averaging 97°F by day and 73°F at night; January is the coldest at 54°F and 30°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 37% of years.
Warmth for growing adds up to 5,877 growing degree days a year (base 50°F), more than at 99% of the 114 Oklahoma stations. 39% of them (2,292) have built up by the end of June, and July adds the most, 1,090.
| Month | High °F | Low °F | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|
| Jan | 54 | 30 | 100% | 20 | 25 |
| Feb | 58 | 33 | 100% | 14 | 59 |
| Mar | 67 | 42 | 95% | 5 | 201 |
| Apr | 76 | 49 | 37% | 1 | 383 |
| May | 84 | 60 | 0% | 0 | 693 |
| Jun | 93 | 69 | 0% | 0 | 931 |
| Jul | 97 | 73 | 0% | 0 | 1090 |
| Aug | 97 | 72 | 0% | 0 | 1065 |
| Sep | 88 | 64 | 0% | 0 | 783 |
| Oct | 77 | 52 | 21% | <1 | 460 |
| Nov | 64 | 41 | 95% | 5 | 154 |
| Dec | 54 | 32 | 100% | 18 | 34 |
Monthly normals 1991–2020 at Altus AFB, OK (1,267 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, Altus Irig Rsch Stn, OK, 24 miles northwest of Frederick, has a last frost 10 days later (April 5), a first frost 8 days earlier (November 2), a season 19 days shorter.
When it snows in Frederick, Oklahoma
Measurable snow is rare here: only 10 of 21 winters from 1991 to 2020 recorded 0.1 inch or more at Chattanooga, OK, 18.1 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 73542
| When | What to do |
|---|---|
| January 15 – January 29 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| January 29 – February 12 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| February 26 – March 12 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| March 26 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 18 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 27 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 10 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 73542 is 3 miles from Altus AFB, OK, which stands at 1,267 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 73542 in zone 8a, the band where the coldest night of the year averaged 10 to 15°F (-12.2 to -9.4°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.