USDA Hardiness Zone 6b
Frost Dates for 66524 — Overbrook, Kansas
NOAA 1991–2020 normals from Pomona Lake, KS (1,063 ft), 9 miles south.
Updated
In Overbrook, the last spring frost (32°F) is around April 8 in half of years and has passed by April 22 in nine years out of ten. The first fall frost comes around October 31, as early as October 18 one year in ten, leaving a typical freeze-free season of 205 days (NOAA, Pomona Lake, KS).
- Last spring frost
- April 8
- First fall frost
- October 31
- Growing season
- 205 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
- December 8
- Last snow
- February 26
- Winters with snow
- 91%
- Snow per year
- 9.9"
median, 1991–2020
median, 1991–2020
20 of 22 observed
NOAA normal
Frost risk by date in Overbrook
Half of springs at Pomona Lake, KS see their last 32°F night by April 8; only one in ten is past it by March 23, and one in ten still has one after April 22. Planting tender crops after April 14 leaves a 30% risk of a frost on them, after April 18 20%, and after April 22 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 44% of the 110 Kansas stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 31 in half of years, as early as October 18 one year in ten, and holds off past November 14 one year in ten. A hard freeze of 28°F follows 8 days later, around November 8; in spring the one-in-ten date for 28°F is April 12, 10 days before the 32°F one. The freeze-free season lasts 205 days in a typical year, longer than at 94% of the 110 Kansas stations; it reaches 227 days one year in ten and falls short of 184 one year in ten. On average 110 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 18, and return around October 22. Severe cold of 16°F or below comes every winter, usually between December 8 and February 28.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 4 | Apr 9 | Apr 13 | Apr 15 | Apr 18 | Apr 21 | Apr 24 | Apr 28 | May 1 |
| 32°F | Mar 23 | Mar 30 | Apr 2 | Apr 5 | Apr 8 | Apr 11 | Apr 14 | Apr 18 | Apr 22 |
| 28°F | Mar 10 | Mar 17 | Mar 22 | Mar 26 | Mar 30 | Apr 1 | Apr 4 | Apr 7 | Apr 12 |
| 24°F | Feb 28 | Mar 4 | Mar 9 | Mar 13 | Mar 17 | Mar 21 | Mar 25 | Mar 30 | Apr 3 |
| 20°F | Feb 19 | Feb 25 | Feb 28 | Mar 3 | Mar 6 | Mar 10 | Mar 13 | Mar 18 | Mar 24 |
| 16°F | Feb 8 | Feb 15 | Feb 20 | Feb 24 | Feb 28 | Mar 2 | Mar 5 | Mar 9 | Mar 16 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 8 | Oct 14 | Oct 18 | Oct 20 | Oct 22 | Oct 24 | Oct 26 | Oct 30 | Nov 2 |
| 32°F | Oct 18 | Oct 22 | Oct 26 | Oct 29 | Oct 31 | Nov 1 | Nov 4 | Nov 8 | Nov 14 |
| 28°F | Oct 27 | Oct 31 | Nov 2 | Nov 5 | Nov 8 | Nov 11 | Nov 14 | Nov 20 | Nov 26 |
| 24°F | Nov 1 | Nov 7 | Nov 12 | Nov 14 | Nov 18 | Nov 22 | Nov 26 | Nov 30 | Dec 5 |
| 20°F | Nov 10 | Nov 16 | Nov 21 | Nov 24 | Nov 29 | Dec 1 | Dec 5 | Dec 9 | Dec 15 |
| 16°F | Nov 20 | Nov 27 | Dec 1 | Dec 5 | Dec 8 | Dec 13 | Dec 18 | Dec 24 | Dec 30 |
Freeze probabilities 1991–2020 at Pomona Lake, KS, 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 66524 →Compare Overbrook with another place →
Frost risk through the year in Overbrook
In Overbrook, the spring curve drops under 10% on April 22 and the fall curve passes 10% on October 18, 179 days later; that gap is longer than at 95% of the 110 Kansas stations with frost dates. The spring risk falls from 90% to 10% over 30 days (March 23 to April 22) and the fall risk climbs from 10% to 90% over 27 days (October 18 to November 14): both ends of the season vary about as much. At Topeka Forbes Field, KS, 14 miles northwest, the same gap runs from April 30 to October 5, 21 days shorter.
| Planted on | Another 32°F night | 28°F night |
|---|---|---|
| Mar 25 | 87% | 63% |
| Apr 1 | 73% | 40% |
| Apr 850% date | 50% | 18% |
| Apr 15 | 28% | under 10% |
| Apr 22 | under 10% | under 10% |
| Apr 29 | under 10% | under 10% |
Weather by month in Overbrook
July is the warmest month at Pomona Lake, KS, averaging 91°F by day and 70°F at night; January is the coldest at 41°F and 22°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 74% of years.
Warmth for growing adds up to 4,327 growing degree days a year (base 50°F), more than at 76% of the 110 Kansas stations. 36% of them (1,559) have built up by the end of June, and July adds the most, 931. Precipitation totals 38.8 inches a year, most in May (5.5") and least in January (1.0"); May to September bring 59% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 41 | 22 | 1.0 | 100% | 28 | 3 |
| Feb | 46 | 24 | 1.7 | 100% | 23 | 12 |
| Mar | 57 | 34 | 2.3 | 99% | 15 | 80 |
| Apr | 67 | 44 | 3.8 | 74% | 3 | 215 |
| May | 76 | 55 | 5.5 | 0% | 0 | 488 |
| Jun | 86 | 65 | 5.4 | 0% | 0 | 762 |
| Jul | 91 | 70 | 3.9 | 0% | 0 | 931 |
| Aug | 89 | 68 | 4.1 | 0% | 0 | 882 |
| Sep | 82 | 59 | 4.0 | 0% | 0 | 602 |
| Oct | 70 | 46 | 3.2 | 52% | 2 | 282 |
| Nov | 56 | 35 | 2.3 | 100% | 13 | 65 |
| Dec | 44 | 26 | 1.6 | 100% | 25 | 7 |
Monthly normals 1991–2020 at Pomona Lake, KS (1,063 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, Topeka Forbes Field, KS, 14 miles northwest of Overbrook, has a last frost 7 days later (April 15), a first frost 10 days earlier (October 21), a season 20 days shorter.
When it snows in Overbrook, Kansas
The first measurable snow (0.1 inch or more) in Overbrook usually arrives around December 8, and the last of the season around February 26. Those are the middle dates across the winters of 1991–2020 at Overbrook 5 SE, KS, 4 miles away: half of years saw snow earlier, half later. Snow fell in 91% of those winters. The last 32°F night of spring typically comes 41 days after the last snow.
Planting calendar for 66524
| When | What to do |
|---|---|
| January 28 – February 11 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 11 – February 25 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 11 – March 25 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 8 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 8 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 17 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 31 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 66524 is 9 miles from Pomona Lake, KS, which stands at 1,063 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 66524 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.