USDA Hardiness Zone 6b
Frost Dates for 47501 — Washington, Indiana
NOAA 1991–2020 normals from Washington 1 W, IN (482 ft), 1 miles southwest.
Updated
In Washington, the last spring frost (32°F) is around April 10 in half of years and has passed by April 27 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 197 days (NOAA, Washington 1 W, IN).
- Last spring frost
- April 10
- First fall frost
- October 25
- Growing season
- 197 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 24
- Last snow
- February 23
- Winters with snow
- 96%
- Snow per year
- 9.2"
median, 1991–2020
median, 1991–2020
26 of 27 observed
NOAA normal
Frost risk by date in Washington
Half of springs at Washington 1 W, IN see their last 32°F night by April 10; only one in ten is past it by March 27, and one in ten still has one after April 27. Planting tender crops after April 17 leaves a 30% risk of a frost on them, after April 21 20%, and after April 27 10%. The 17 days between the even-odds date and the one-in-ten date is wider than at 66% of the 125 Indiana 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 7 one year in ten. A hard freeze of 28°F follows 10 days later, around November 4; in spring the one-in-ten date for 28°F is April 15, 12 days before the 32°F one. The freeze-free season lasts 197 days in a typical year, longer than at 82% of the 125 Indiana stations; it reaches 216 days one year in ten and falls short of 174 one year in ten. On average 90 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 22, and return around October 15. Severe cold of 16°F or below comes every winter, usually between December 7 and February 26.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 8 | Apr 13 | Apr 16 | Apr 19 | Apr 22 | Apr 25 | Apr 29 | May 2 | May 8 |
| 32°F | Mar 27 | Mar 31 | Apr 4 | Apr 7 | Apr 10 | Apr 14 | Apr 17 | Apr 21 | Apr 27 |
| 28°F | Mar 14 | Mar 20 | Mar 24 | Mar 28 | Mar 30 | Apr 1 | Apr 5 | Apr 10 | Apr 15 |
| 24°F | Mar 1 | Mar 8 | Mar 13 | Mar 17 | Mar 20 | Mar 24 | Mar 27 | Mar 30 | Apr 4 |
| 20°F | Feb 17 | Feb 25 | Mar 1 | Mar 4 | Mar 8 | Mar 11 | Mar 15 | Mar 19 | Mar 26 |
| 16°F | Feb 3 | Feb 10 | Feb 17 | Feb 23 | Feb 26 | Mar 3 | Mar 6 | Mar 11 | Mar 17 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 1 | Oct 7 | Oct 11 | Oct 13 | Oct 15 | Oct 18 | Oct 21 | Oct 23 | Oct 28 |
| 32°F | Oct 11 | Oct 17 | Oct 20 | Oct 23 | Oct 25 | Oct 28 | Oct 30 | Nov 2 | Nov 7 |
| 28°F | Oct 22 | Oct 27 | Oct 31 | Nov 1 | Nov 4 | Nov 7 | Nov 10 | Nov 14 | Nov 20 |
| 24°F | Nov 1 | Nov 5 | Nov 9 | Nov 12 | Nov 15 | Nov 19 | Nov 23 | Nov 27 | Dec 3 |
| 20°F | Nov 9 | Nov 15 | Nov 19 | Nov 24 | Nov 27 | Dec 1 | Dec 3 | Dec 8 | Dec 16 |
| 16°F | Nov 17 | Nov 25 | Nov 30 | Dec 3 | Dec 7 | Dec 11 | Dec 18 | Dec 24 | Dec 30 |
Freeze probabilities 1991–2020 at Washington 1 W, IN, 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 47501 →Compare Washington with another place →
Weather by month in Washington
July is the warmest month at Washington 1 W, IN, averaging 87°F by day and 67°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 78% of years.
Warmth for growing adds up to 4,206 growing degree days a year (base 50°F), more than at 93% of the 125 Indiana stations. 38% of them (1,614) have built up by the end of June, and July adds the most, 840. Precipitation totals 48.0 inches a year, most in May (5.5") and least in February (2.9"); May to September bring 45% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 40 | 24 | 3.6 | 100% | 23 | 8 |
| Feb | 46 | 28 | 2.9 | 100% | 19 | 18 |
| Mar | 57 | 36 | 4.0 | 99% | 12 | 84 |
| Apr | 69 | 45 | 4.8 | 78% | 3 | 251 |
| May | 77 | 56 | 5.5 | 6% | 0 | 519 |
| Jun | 85 | 64 | 5.2 | 0% | 0 | 733 |
| Jul | 87 | 67 | 4.1 | 0% | 0 | 840 |
| Aug | 86 | 65 | 3.2 | 0% | 0 | 797 |
| Sep | 81 | 58 | 3.5 | 2% | 0 | 581 |
| Oct | 70 | 47 | 3.6 | 74% | 2 | 289 |
| Nov | 56 | 36 | 3.9 | 100% | 11 | 73 |
| Dec | 45 | 28 | 3.7 | 100% | 20 | 14 |
Monthly normals 1991–2020 at Washington 1 W, IN (482 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, Petersburg 61 Brg, IN, 14 miles south of Washington, has a last frost 10 days later (April 20), a first frost 3 days earlier (October 22), a season 11 days shorter.
When it snows in Washington, Indiana
The first measurable snow (0.1 inch or more) in Washington usually arrives around December 24, and the last of the season around February 23. Those are the middle dates across the winters of 1991–2020 at Washington 1 W, IN, 1.4 miles away: half of years saw snow earlier, half later. Snow fell in 96% of those winters. The last 32°F night of spring typically comes 46 days after the last snow.
Planting calendar for 47501
| When | What to do |
|---|---|
| January 30 – February 13 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 13 – February 27 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 13 – March 27 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 10 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 47501 is 1 mile from Washington 1 W, IN, which stands at 482 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 47501 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.