USDA Hardiness Zone 6b
Frost Dates for 66064 — Osawatomie, Kansas
NOAA 1991–2020 normals from Osawatomie, KS (860 ft), under a mile north.
Updated
In Osawatomie, the last spring frost (32°F) is around April 14 in half of years and has passed by April 29 in nine years out of ten. The first fall frost comes around October 25, as early as October 11 one year in ten, leaving a typical freeze-free season of 192 days (NOAA, Osawatomie, KS).
- Last spring frost
- April 14
- First fall frost
- October 25
- Growing season
- 192 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 23
- Last snow
- February 25
- Winters with snow
- 78%
- Snow per year
- 8.4"
median, 1991–2020
median, 1991–2020
21 of 27 observed
NOAA normal
Frost risk by date in Osawatomie
Half of springs at Osawatomie, KS see their last 32°F night by April 14; only one in ten is past it by March 31, and one in ten still has one after April 29. Planting tender crops after April 19 leaves a 30% risk of a frost on them, after April 23 20%, and after April 29 10%. The 15 days between the even-odds date and the one-in-ten date is wider than at 57% of the 110 Kansas stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 25 in half of years, as early as October 11 one year in ten, and holds off past November 5 one year in ten. A hard freeze of 28°F follows 9 days later, around November 3; in spring the one-in-ten date for 28°F is April 18, 11 days before the 32°F one. The freeze-free season lasts 192 days in a typical year, longer than at 65% of the 110 Kansas stations; it reaches 211 days one year in ten and falls short of 172 one year in ten. On average 114 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 9 days longer, to about April 23, and return around October 15. Severe cold of 16°F or below comes every winter, usually between December 1 and March 5.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 9 | Apr 14 | Apr 17 | Apr 20 | Apr 23 | Apr 27 | Apr 30 | May 2 | May 6 |
| 32°F | Mar 31 | Apr 5 | Apr 8 | Apr 11 | Apr 14 | Apr 16 | Apr 19 | Apr 23 | Apr 29 |
| 28°F | Mar 19 | Mar 25 | Mar 30 | Apr 1 | Apr 3 | Apr 6 | Apr 9 | Apr 12 | Apr 18 |
| 24°F | Mar 8 | Mar 13 | Mar 18 | Mar 22 | Mar 26 | Mar 29 | Apr 1 | Apr 5 | Apr 9 |
| 20°F | Feb 27 | Mar 3 | Mar 7 | Mar 11 | Mar 14 | Mar 18 | Mar 22 | Mar 27 | Apr 1 |
| 16°F | Feb 17 | Feb 23 | Feb 28 | Mar 2 | Mar 5 | Mar 8 | Mar 11 | Mar 15 | Mar 20 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 30 | Oct 6 | Oct 10 | Oct 12 | Oct 15 | Oct 18 | Oct 20 | Oct 23 | Oct 27 |
| 32°F | Oct 11 | Oct 16 | Oct 19 | Oct 22 | Oct 25 | Oct 27 | Oct 30 | Nov 1 | Nov 5 |
| 28°F | Oct 21 | Oct 26 | Oct 29 | Nov 1 | Nov 3 | Nov 5 | Nov 8 | Nov 11 | Nov 18 |
| 24°F | Oct 31 | Nov 3 | Nov 5 | Nov 8 | Nov 11 | Nov 15 | Nov 18 | Nov 24 | Nov 30 |
| 20°F | Nov 5 | Nov 10 | Nov 14 | Nov 17 | Nov 21 | Nov 25 | Nov 30 | Dec 3 | Dec 9 |
| 16°F | Nov 13 | Nov 19 | Nov 24 | Nov 28 | Dec 1 | Dec 5 | Dec 8 | Dec 14 | Dec 20 |
Freeze probabilities 1991–2020 at Osawatomie, 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 66064 →Compare Osawatomie with another place →
Compared with the next station
The nearest other station, Paola, KS, 8 miles northeast of Osawatomie, has a last frost 1 day earlier (April 13), a first frost 4 days earlier (October 21), a season 1 day shorter.
When it snows in Osawatomie, Kansas
The first measurable snow (0.1 inch or more) in Osawatomie usually arrives around December 23, and the last of the season around February 25. Those are the middle dates across the winters of 1991–2020 at Osawatomie, KS, 0.9 miles away: half of years saw snow earlier, half later. Snow fell in 78% of those winters. The last 32°F night of spring typically comes 48 days after the last snow.
Planting calendar for 66064
| When | What to do |
|---|---|
| February 3 – February 17 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 17 – March 3 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 17 – March 31 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 14 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 2 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 11 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 25 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 66064 is under a mile from Osawatomie, KS, which stands at 860 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 66064 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.