USDA Hardiness Zone 6b
Frost Dates for 63670 — Ste Genevieve, Missouri
NOAA 1991–2020 normals from Kaskaskia Rvr Navigation Lock, IL (380 ft), 12 miles northeast.
Updated
In Ste Genevieve, the last spring frost (32°F) is around April 8 in half of years and has passed by April 25 in nine years out of ten. The first fall frost comes around October 30, as early as October 15 one year in ten, leaving a typical freeze-free season of 202 days (NOAA, Kaskaskia Rvr Navigation Lock, IL).
- Last spring frost
- April 8
- First fall frost
- October 30
- Growing season
- 202 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 1
- Winters with snow
- 95%
- Snow per year
- 4.3"
median, 1991–2020
median, 1991–2020
20 of 21 observed
NOAA normal
Frost risk by date in Ste Genevieve
Half of springs at Kaskaskia Rvr Navigation Lock, IL see their last 32°F night by April 8; only one in ten is past it by March 22, and one in ten still has one after April 25. Planting tender crops after April 15 leaves a 30% risk of a frost on them, after April 19 20%, and after April 25 10%. The 17 days between the even-odds date and the one-in-ten date is wider than at 66% of the 158 Missouri stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 30 in half of years, as early as October 15 one year in ten, and holds off past November 13 one year in ten. A hard freeze of 28°F follows 11 days later, around November 10; in spring the one-in-ten date for 28°F is April 13, 12 days before the 32°F one. The freeze-free season lasts 202 days in a typical year, longer than at 73% of the 158 Missouri stations; it reaches 226 days one year in ten and falls short of 180 one year in ten. On average 99 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 12 days longer, to about April 20, and return around October 18. Severe cold of 16°F or below comes every winter, usually between December 16 and February 24.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 5 | Apr 10 | Apr 14 | Apr 17 | Apr 20 | Apr 23 | Apr 26 | Apr 30 | May 5 |
| 32°F | Mar 22 | Mar 29 | Apr 2 | Apr 5 | Apr 8 | Apr 11 | Apr 15 | Apr 19 | Apr 25 |
| 28°F | Mar 9 | Mar 15 | Mar 19 | Mar 23 | Mar 28 | Mar 31 | Apr 3 | Apr 7 | Apr 13 |
| 24°F | Feb 26 | Mar 3 | Mar 7 | Mar 10 | Mar 14 | Mar 18 | Mar 22 | Mar 27 | Apr 2 |
| 20°F | Feb 9 | Feb 20 | Feb 26 | Mar 1 | Mar 4 | Mar 8 | Mar 12 | Mar 16 | Mar 22 |
| 16°F | Jan 30 | Feb 5 | Feb 11 | Feb 18 | Feb 24 | Feb 28 | Mar 4 | Mar 8 | Mar 14 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 4 | Oct 9 | Oct 12 | Oct 15 | Oct 18 | Oct 20 | Oct 23 | Oct 27 | Oct 31 |
| 32°F | Oct 15 | Oct 20 | Oct 24 | Oct 28 | Oct 30 | Nov 1 | Nov 4 | Nov 8 | Nov 13 |
| 28°F | Oct 27 | Nov 1 | Nov 3 | Nov 6 | Nov 10 | Nov 13 | Nov 18 | Nov 23 | Nov 30 |
| 24°F | Nov 5 | Nov 12 | Nov 16 | Nov 20 | Nov 24 | Nov 28 | Dec 1 | Dec 5 | Dec 12 |
| 20°F | Nov 16 | Nov 23 | Nov 28 | Dec 1 | Dec 4 | Dec 8 | Dec 13 | Dec 18 | Dec 24 |
| 16°F | Nov 27 | Dec 1 | Dec 7 | Dec 11 | Dec 16 | Dec 21 | Dec 26 | Dec 30 | Jan 7 |
Freeze probabilities 1991–2020 at Kaskaskia Rvr Navigation Lock, IL, 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 63670 →Compare Ste Genevieve with another place →
Weather by month in Ste Genevieve
July is the warmest month at Kaskaskia Rvr Navigation Lock, IL, averaging 89°F by day and 68°F at night; January is the coldest at 40°F and 24°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 73% of years.
Warmth for growing adds up to 4,230 growing degree days a year (base 50°F), more than at 73% of the 158 Missouri stations. 37% of them (1,568) have built up by the end of June, and July adds the most, 890. Precipitation totals 42.8 inches a year, most in May (5.2") and least in February (2.4"); May to September bring 46% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 40 | 24 | 2.7 | 100% | 25 | 7 |
| Feb | 46 | 27 | 2.4 | 100% | 21 | 15 |
| Mar | 56 | 35 | 3.4 | 99% | 13 | 75 |
| Apr | 68 | 44 | 4.7 | 73% | 3 | 222 |
| May | 77 | 55 | 5.2 | 4% | 0 | 496 |
| Jun | 86 | 64 | 4.1 | 0% | 0 | 753 |
| Jul | 89 | 68 | 4.1 | 0% | 0 | 890 |
| Aug | 88 | 66 | 3.3 | 0% | 0 | 828 |
| Sep | 81 | 58 | 2.9 | 0% | 0 | 587 |
| Oct | 70 | 46 | 3.1 | 55% | 2 | 276 |
| Nov | 56 | 37 | 4.0 | 99% | 13 | 70 |
| Dec | 44 | 28 | 2.9 | 100% | 22 | 12 |
Monthly normals 1991–2020 at Kaskaskia Rvr Navigation Lock, IL (380 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, Farmington, MO, 16 miles southwest of Ste Genevieve and 520 feet higher, has a last frost 5 days later (April 13), a first frost 9 days earlier (October 21), a season 11 days shorter.
When it snows in Ste Genevieve, Missouri
The first measurable snow (0.1 inch or more) in Ste Genevieve usually arrives around December 23, and the last of the season around February 1. Those are the middle dates across the winters of 1991–2020 at Kaskaskia Rvr Navigation Lock, IL, 12.2 miles away: half of years saw snow earlier, half later. Snow fell in 95% of those winters. The last 32°F night of spring typically comes 66 days after the last snow.
Planting calendar for 63670
| 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 7 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 16 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 30 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 63670 is 12 miles from Kaskaskia Rvr Navigation Lock, IL, which stands at 380 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 63670 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.