USDA Hardiness Zone 7b
Frost Dates for 74820 — Ada, Oklahoma
NOAA 1991–2020 normals from Ada, OK (1,015 ft), under a mile north.
Updated
In Ada, the last spring frost (32°F) is around April 2 in half of years and has passed by April 18 in nine years out of ten. The first fall frost comes around November 4, as early as October 20 one year in ten, leaving a typical freeze-free season of 217 days (NOAA, Ada, OK).
- Last spring frost
- April 2
- First fall frost
- November 4
- Growing season
- 217 days
- Hardiness zone
- 7b
50% probability
50% probability
freeze-free, 50%
5 to 10°F (-15.0 to -12.2°C) coldest night
- First snow
- December 27
- Last snow
- February 2
- Winters with snow
- 70%
- Snow per year
- 4.1"
median, 1991–2020
median, 1991–2020
14 of 20 observed
NOAA normal
Frost risk by date in Ada
Half of springs at Ada, OK see their last 32°F night by April 2; only one in ten is past it by March 14, and one in ten still has one after April 18. Planting tender crops after April 8 leaves a 30% risk of a frost on them, after April 11 20%, and after April 18 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 61% of the 114 Oklahoma stations behind this site's ZIP pages.
In fall the first 32°F night comes by November 4 in half of years, as early as October 20 one year in ten, and holds off past November 21 one year in ten. A hard freeze of 28°F follows 9 days later, around November 13; in spring the one-in-ten date for 28°F is April 7, 11 days before the 32°F one. The freeze-free season lasts 217 days in a typical year, longer than at 70% of the 114 Oklahoma stations; it reaches 239 days one year in ten and falls short of 194 one year in ten. On average 72 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 12, and return around October 26. Severe cold of 16°F or below comes in 97% of winters, usually between December 24 and February 9.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Mar 27 | Apr 2 | Apr 5 | Apr 9 | Apr 12 | Apr 15 | Apr 19 | Apr 23 | Apr 27 |
| 32°F | Mar 14 | Mar 21 | Mar 26 | Mar 30 | Apr 2 | Apr 5 | Apr 8 | Apr 11 | Apr 18 |
| 28°F | Feb 28 | Mar 6 | Mar 11 | Mar 15 | Mar 19 | Mar 24 | Mar 29 | Apr 2 | Apr 7 |
| 24°F | Feb 15 | Feb 23 | Feb 28 | Mar 3 | Mar 6 | Mar 10 | Mar 13 | Mar 18 | Mar 26 |
| 20°F | Jan 31 | Feb 9 | Feb 15 | Feb 21 | Feb 25 | Mar 1 | Mar 4 | Mar 9 | Mar 14 |
| 16°F97% of yrs | Jan 13 | Jan 24 | Jan 30 | Feb 3 | Feb 9 | Feb 15 | Feb 22 | Feb 28 | Mar 6 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 11 | Oct 17 | Oct 20 | Oct 23 | Oct 26 | Oct 28 | Oct 31 | Nov 4 | Nov 9 |
| 32°F | Oct 20 | Oct 26 | Oct 30 | Nov 1 | Nov 4 | Nov 7 | Nov 11 | Nov 15 | Nov 21 |
| 28°F | Oct 28 | Nov 2 | Nov 6 | Nov 10 | Nov 13 | Nov 16 | Nov 21 | Nov 26 | Dec 1 |
| 24°F | Nov 4 | Nov 12 | Nov 16 | Nov 20 | Nov 25 | Nov 29 | Dec 3 | Dec 7 | Dec 14 |
| 20°F | Nov 16 | Nov 24 | Nov 30 | Dec 3 | Dec 8 | Dec 13 | Dec 19 | Dec 25 | Jan 1 |
| 16°F97% of yrs | Nov 29 | Dec 6 | Dec 13 | Dec 18 | Dec 24 | Dec 30 | Jan 5 | Jan 11 | Jan 23 |
Freeze probabilities 1991–2020 at Ada, 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 74820 →Compare Ada with another place →
Weather by month in Ada
July is the warmest month at Ada, OK, averaging 94°F by day and 72°F at night; January is the coldest at 52°F and 27°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 55% of years.
Warmth for growing adds up to 5,278 growing degree days a year (base 50°F), more than at 69% of the 114 Oklahoma stations. 38% of them (1,996) have built up by the end of June, and July adds the most, 1,018. Precipitation totals 41.6 inches a year, most in May (5.4") and least in February (2.1"); May to September bring 49% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 52 | 27 | 2.2 | 100% | 22 | 18 |
| Feb | 57 | 31 | 2.1 | 100% | 16 | 45 |
| Mar | 65 | 39 | 3.5 | 97% | 7 | 157 |
| Apr | 73 | 48 | 4.0 | 55% | 1 | 327 |
| May | 80 | 59 | 5.4 | 0% | 0 | 603 |
| Jun | 89 | 68 | 4.7 | 0% | 0 | 846 |
| Jul | 94 | 72 | 3.0 | 0% | 0 | 1018 |
| Aug | 94 | 70 | 3.1 | 0% | 0 | 989 |
| Sep | 86 | 62 | 4.3 | 0% | 0 | 714 |
| Oct | 75 | 50 | 4.1 | 36% | 1 | 396 |
| Nov | 64 | 39 | 2.5 | 96% | 7 | 135 |
| Dec | 54 | 30 | 2.7 | 100% | 18 | 30 |
Monthly normals 1991–2020 at Ada, OK (1,015 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, Ada 2NNE Mesonet, OK, 2 miles northeast of Ada, has a last frost 2 days earlier (March 31), a first frost 1 day earlier (November 3), a season 1 day shorter.
When it snows in Ada, Oklahoma
The first measurable snow (0.1 inch or more) in Ada usually arrives around December 27, and the last of the season around February 2. Those are the middle dates across the winters of 1991–2020 at Ada, OK, 0.5 miles away: half of years saw snow earlier, half later. Snow fell in 70% of those winters. The last 32°F night of spring typically comes 59 days after the last snow.
Planting calendar for 74820
| When | What to do |
|---|---|
| January 22 – February 5 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 5 – February 19 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 5 – March 19 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 2 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 12 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 21 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 4 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 74820 is under a mile from Ada, OK, which stands at 1,015 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 74820 in zone 7b, the band where the coldest night of the year averaged 5 to 10°F (-15.0 to -12.2°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.