USDA Hardiness Zone 6b
Frost Dates for 45750 — Marietta, Ohio
NOAA 1991–2020 normals from Marietta Wwtp, OH (610 ft), 1 miles southeast.
Updated
In Marietta, the last spring frost (32°F) is around April 18 in half of years and has passed by May 4 in nine years out of ten. The first fall frost comes around October 27, as early as October 13 one year in ten, leaving a typical freeze-free season of 191 days (NOAA, Marietta Wwtp, OH).
- Last spring frost
- April 18
- First fall frost
- October 27
- Growing season
- 191 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 19
- Last snow
- March 6
- Winters with snow
- 100%
- Snow per year
- 16.3"
median, 1991–2020
median, 1991–2020
26 of 26 observed
NOAA normal
Frost risk by date in Marietta
Half of springs at Marietta Wwtp, OH see their last 32°F night by April 18; only one in ten is past it by April 5, and one in ten still has one after May 4. Planting tender crops after April 24 leaves a 30% risk of a frost on them, after April 29 20%, and after May 4 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 53% of the 148 Ohio stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 27 in half of years, as early as October 13 one year in ten, and holds off past November 6 one year in ten. A hard freeze of 28°F follows 9 days later, around November 5; in spring the one-in-ten date for 28°F is April 19, 15 days before the 32°F one. The freeze-free season lasts 191 days in a typical year, longer than at 84% of the 148 Ohio stations; it reaches 210 days one year in ten and falls short of 171 one year in ten. On average 112 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 30, and return around October 16. Severe cold of 16°F or below comes every winter, usually between December 17 and March 3.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 16 | Apr 20 | Apr 23 | Apr 27 | Apr 30 | May 3 | May 6 | May 10 | May 17 |
| 32°F | Apr 5 | Apr 9 | Apr 13 | Apr 16 | Apr 18 | Apr 21 | Apr 24 | Apr 29 | May 4 |
| 28°F | Mar 22 | Mar 27 | Mar 31 | Apr 2 | Apr 5 | Apr 7 | Apr 11 | Apr 14 | Apr 19 |
| 24°F | Mar 8 | Mar 15 | Mar 18 | Mar 21 | Mar 24 | Mar 27 | Mar 30 | Apr 2 | Apr 6 |
| 20°F | Feb 24 | Mar 2 | Mar 7 | Mar 11 | Mar 14 | Mar 17 | Mar 19 | Mar 23 | Mar 28 |
| 16°F | Feb 9 | Feb 16 | Feb 22 | Feb 28 | Mar 3 | Mar 6 | Mar 10 | Mar 14 | Mar 19 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 3 | Oct 7 | Oct 10 | Oct 14 | Oct 16 | Oct 18 | Oct 21 | Oct 24 | Oct 29 |
| 32°F | Oct 13 | Oct 17 | Oct 20 | Oct 24 | Oct 27 | Oct 30 | Nov 1 | Nov 3 | Nov 6 |
| 28°F | Oct 24 | Oct 29 | Nov 1 | Nov 2 | Nov 5 | Nov 8 | Nov 11 | Nov 14 | Nov 19 |
| 24°F | Nov 2 | Nov 6 | Nov 9 | Nov 12 | Nov 15 | Nov 18 | Nov 22 | Nov 27 | Dec 4 |
| 20°F | Nov 11 | Nov 17 | Nov 21 | Nov 26 | Nov 30 | Dec 4 | Dec 9 | Dec 16 | Dec 24 |
| 16°F | Nov 22 | Nov 30 | Dec 6 | Dec 11 | Dec 17 | Dec 23 | Dec 27 | Jan 1 | Jan 8 |
Freeze probabilities 1991–2020 at Marietta Wwtp, OH, 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 45750 →Compare Marietta with another place →
Frost risk through the year in Marietta
In Marietta, the spring curve drops under 10% on May 4 and the fall curve passes 10% on October 13, 162 days later; that gap is longer than at 85% of the 148 Ohio stations with frost dates. The spring risk falls from 90% to 10% over 29 days (April 5 to May 4) and the fall risk climbs from 10% to 90% over 24 days (October 13 to November 6): both ends of the season vary about as much. At Parkersburg Wood Co Airport, WV, 6 miles south, the same gap runs from May 11 to October 8, 12 days shorter.
| Planted on | Another 32°F night | 28°F night |
|---|---|---|
| Apr 4 | over 90% | 53% |
| Apr 11 | 75% | 30% |
| Apr 1850% date | 50% | 12% |
| Apr 25 | 28% | under 10% |
| May 2 | 14% | under 10% |
| May 9 | under 10% | under 10% |
Weather by month in Marietta
July is the warmest month at Marietta Wwtp, OH, averaging 85°F by day and 65°F at night; January is the coldest at 40°F and 23°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 14% of years.
Warmth for growing adds up to 3,587 growing degree days a year (base 50°F), more than at 84% of the 148 Ohio stations. 36% of them (1,278) have built up by the end of June, and July adds the most, 784. Precipitation totals 45.4 inches a year, most in June (4.9") and least in November (2.9"); 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 | 23 | 3.5 | 100% | 25 | 6 |
| Feb | 43 | 24 | 3.1 | 100% | 22 | 7 |
| Mar | 53 | 31 | 4.0 | 100% | 18 | 43 |
| Apr | 66 | 41 | 4.0 | 96% | 6 | 169 |
| May | 75 | 52 | 4.4 | 14% | <1 | 414 |
| Jun | 82 | 61 | 4.9 | 0% | 0 | 640 |
| Jul | 85 | 65 | 4.8 | 0% | 0 | 784 |
| Aug | 85 | 63 | 3.6 | 0% | 0 | 744 |
| Sep | 79 | 56 | 3.4 | 0% | 0 | 523 |
| Oct | 67 | 44 | 3.2 | 67% | 3 | 203 |
| Nov | 54 | 34 | 2.9 | 100% | 15 | 44 |
| Dec | 44 | 28 | 3.6 | 100% | 22 | 11 |
Monthly normals 1991–2020 at Marietta Wwtp, OH (610 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, Parkersburg Wood Co Airport, WV, 6 miles south of Marietta and 221 feet higher, has a last frost 5 days later (April 23), a first frost 5 days earlier (October 22), a season 11 days shorter.
When it snows in Marietta, Ohio
The first measurable snow (0.1 inch or more) in Marietta usually arrives around December 19, and the last of the season around March 6. Those are the middle dates across the winters of 1991–2020 at Marietta Wwtp, OH, 1.4 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 43 days after the last snow.
Planting calendar for 45750
| When | What to do |
|---|---|
| February 7 – February 21 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 21 – March 7 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 21 – April 4 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 18 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 4 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 13 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 27 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 45750 is 1 mile from Marietta Wwtp, OH, which stands at 610 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 45750 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.