USDA Hardiness Zone 5b
Frost Dates for 64673 — Princeton, Missouri
NOAA 1991–2020 normals from Princeton, MO (980 ft), under a mile north.
Updated
In Princeton, the last spring frost (32°F) is around April 25 in half of years and has passed by May 8 in nine years out of ten. The first fall frost comes around October 15, as early as September 30 one year in ten, leaving a typical freeze-free season of 174 days (NOAA, Princeton, MO).
- Last spring frost
- April 25
- First fall frost
- October 15
- Growing season
- 174 days
- Hardiness zone
- 5b
50% probability
50% probability
freeze-free, 50%
-15 to -10°F (-26.1 to -23.3°C) coldest night
- First snow
- December 9
- Last snow
- March 7
- Winters with snow
- 73%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
19 of 26 observed
NOAA normal
Frost risk by date in Princeton
Half of springs at Princeton, MO see their last 32°F night by April 25; only one in ten is past it by April 11, and one in ten still has one after May 8. Planting tender crops after May 1 leaves a 30% risk of a frost on them, after May 4 20%, and after May 8 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 94% of the 158 Missouri stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 15 in half of years, as early as September 30 one year in ten, and holds off past October 29 one year in ten. A hard freeze of 28°F follows 11 days later, around October 26; in spring the one-in-ten date for 28°F is April 28, 10 days before the 32°F one. The freeze-free season lasts 174 days in a typical year, shorter than at 97% of the 158 Missouri stations; it reaches 194 days one year in ten and falls short of 152 one year in ten. On average 127 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 May 5, and return around October 5. Severe cold of 16°F or below comes every winter, usually between November 22 and March 13.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 20 | Apr 26 | Apr 30 | May 2 | May 5 | May 7 | May 9 | May 13 | May 18 |
| 32°F | Apr 11 | Apr 15 | Apr 18 | Apr 21 | Apr 25 | Apr 28 | May 1 | May 4 | May 8 |
| 28°F | Mar 31 | Apr 4 | Apr 7 | Apr 10 | Apr 14 | Apr 16 | Apr 20 | Apr 23 | Apr 28 |
| 24°F | Mar 17 | Mar 24 | Mar 28 | Mar 31 | Apr 3 | Apr 5 | Apr 8 | Apr 11 | Apr 16 |
| 20°F | Mar 5 | Mar 11 | Mar 16 | Mar 20 | Mar 23 | Mar 27 | Mar 31 | Apr 3 | Apr 8 |
| 16°F | Feb 25 | Mar 2 | Mar 6 | Mar 9 | Mar 13 | Mar 16 | Mar 20 | Mar 25 | Mar 31 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 21 | Sep 26 | Sep 29 | Oct 2 | Oct 5 | Oct 8 | Oct 11 | Oct 14 | Oct 19 |
| 32°F | Sep 30 | Oct 5 | Oct 9 | Oct 13 | Oct 15 | Oct 18 | Oct 21 | Oct 25 | Oct 29 |
| 28°F | Oct 11 | Oct 17 | Oct 21 | Oct 23 | Oct 26 | Oct 29 | Oct 31 | Nov 2 | Nov 8 |
| 24°F | Oct 21 | Oct 26 | Oct 30 | Nov 1 | Nov 3 | Nov 6 | Nov 9 | Nov 13 | Nov 18 |
| 20°F | Oct 31 | Nov 3 | Nov 6 | Nov 9 | Nov 12 | Nov 15 | Nov 19 | Nov 24 | Dec 1 |
| 16°F | Nov 6 | Nov 11 | Nov 15 | Nov 19 | Nov 22 | Nov 26 | Nov 30 | Dec 3 | Dec 9 |
Freeze probabilities 1991–2020 at Princeton, MO, 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 64673 →Compare Princeton with another place →
Weather by month in Princeton
July is the warmest month at Princeton, MO, averaging 86°F by day and 65°F at night; January is the coldest at 34°F and 15°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 30% of years.
Warmth for growing adds up to 3,378 growing degree days a year (base 50°F), fewer than at 97% of the 158 Missouri stations. 35% of them (1,171) have built up by the end of June, and July adds the most, 792. Precipitation totals 38.0 inches a year, most in June (5.6") and least in January (1.1"); May to September bring 60% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 34 | 15 | 1.1 | 100% | 29 | 0 |
| Feb | 39 | 18 | 1.2 | 100% | 24 | 4 |
| Mar | 51 | 29 | 2.2 | 100% | 19 | 41 |
| Apr | 63 | 39 | 4.2 | 99% | 6 | 134 |
| May | 72 | 50 | 5.1 | 30% | <1 | 358 |
| Jun | 81 | 61 | 5.6 | 0% | 0 | 634 |
| Jul | 86 | 65 | 3.9 | 0% | 0 | 792 |
| Aug | 84 | 63 | 4.3 | 0% | 0 | 731 |
| Sep | 77 | 54 | 3.8 | 11% | <1 | 464 |
| Oct | 65 | 42 | 3.3 | 94% | 5 | 185 |
| Nov | 51 | 30 | 1.9 | 100% | 17 | 33 |
| Dec | 38 | 20 | 1.4 | 100% | 27 | 2 |
Monthly normals 1991–2020 at Princeton, MO (980 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, Trenton, MO, 21 miles south of Princeton, has a last frost 9 days earlier (April 16), a first frost 5 days later (October 20), a season 10 days longer.
When it snows in Princeton, Missouri
The first measurable snow (0.1 inch or more) in Princeton usually arrives around December 9, and the last of the season around March 7. Those are the middle dates across the winters of 1991–2020 at Princeton, MO, 0.5 miles away: half of years saw snow earlier, half later. Snow fell in 73% of those winters. The last 32°F night of spring typically comes 49 days after the last snow.
Planting calendar for 64673
| When | What to do |
|---|---|
| February 14 – February 28 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 28 – March 14 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 28 – April 11 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 25 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 23 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 1 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 15 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 64673 is under a mile from Princeton, MO, which stands at 980 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 64673 in zone 5b, the band where the coldest night of the year averaged -15 to -10°F (-26.1 to -23.3°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.