Williamstown, Kentucky climate: Normal weather by month, frost dates and records
Williamstown's normal year runs from 25°F January nights to 87°F July afternoons, with 45.9 inches of precipitation and 16 inches of snow a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 13.6°C, January lows of −4°C, July highs of 31°C, 1,165 mm of precipitation a year.
- NOAA stationWilliamstown
- Station IDUSC00158714
- Location38.64°N 84.56°W
- Elevation969 ft (295 m)
- From the centerunder 1 mile
- Population3,971
On October 23, the normal high in Williamstown is 67°F and the normal low 45°F, and the chance of measurable rain or snow is 32%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Williamstown.
- Jan 42° 25°
- Feb 47° 28°
- Mar 56° 35°
- Apr 68° 45°
- May 77° 55°
- Jun 83° 63°
- Jul 87° 66°
- Aug 86° 65°
- Sep 81° 58°
- Oct 70° 47°
- Nov 56° 37°
- Dec 46° 29°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Williamstown each month?
July is the warmest month, with normal highs of 87°F; January the coldest, with normal lows of 25°F. The most precipitation falls in June (4.99 in), the least in October (3.00 in).
| Month | High | Low | Mean | Precip. | Snow | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | 42°F | 25°F | 33.4°F | 3.12 | 6.7 | 14 | <1 | 24 | 9 h 40 min |
| February | 47°F | 28°F | 37.5°F | 3.26 | 4.1 | 12 | <1 | 19 | 10 h 40 min |
| March | 56°F | 35°F | 45.6°F | 4.34 | 1.7 | 14 | <1 | 13 | 11 h 50 min |
| April | 68°F | 45°F | 56.7°F | 4.14 | 0.1 | 14 | <1 | 3 | 13 h 10 min |
| May | 77°F | 55°F | 65.7°F | 4.87 | 0.0 | 14 | <1 | <1 | 14 h 10 min |
| June | 83°F | 63°F | 73.0°F | 4.99 | 0.0 | 12 | 4 | <1 | 14 h 50 min |
| July | 87°F | 66°F | 76.7°F | 3.82 | 0.0 | 11 | 9 | <1 | 14 h 40 min |
| August | 86°F | 65°F | 75.5°F | 3.80 | 0.0 | 9 | 8 | <1 | 13 h 40 min |
| September | 81°F | 58°F | 69.7°F | 3.46 | 0.0 | 8 | 3 | <1 | 12 h 30 min |
| October | 70°F | 47°F | 58.5°F | 3.00 | 0.2 | 9 | <1 | 2 | 11 h 20 min |
| November | 56°F | 37°F | 46.7°F | 3.55 | 0.4 | 11 | <1 | 11 | 10 h 10 min |
| December | 46°F | 29°F | 37.4°F | 3.51 | 2.8 | 14 | <1 | 19 | 9 h 30 min |
| Year (annual) | 67°F | 46°F | 56.4°F | 45.86 | 16.0 | 142 | 23 | 91 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. | Snow |
|---|---|---|---|---|---|
| January | 5°C | −4°C | 0.8°C | 79 mm | 17 cm |
| February | 8°C | −2°C | 3.1°C | 83 mm | 10 cm |
| March | 13°C | 2°C | 7.6°C | 110 mm | 4 cm |
| April | 20°C | 7°C | 13.7°C | 105 mm | 0 cm |
| May | 25°C | 13°C | 18.7°C | 124 mm | 0 cm |
| June | 29°C | 17°C | 22.8°C | 127 mm | 0 cm |
| July | 31°C | 19°C | 24.8°C | 97 mm | 0 cm |
| August | 30°C | 18°C | 24.2°C | 97 mm | 0 cm |
| September | 27°C | 15°C | 20.9°C | 88 mm | 0 cm |
| October | 21°C | 8°C | 14.7°C | 76 mm | 1 cm |
| November | 13°C | 3°C | 8.2°C | 90 mm | 1 cm |
| December | 8°C | −2°C | 3.0°C | 89 mm | 7 cm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00158714; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Williamstown?
Normal highs sit between 65°F and 85°F in April, May, June, September and October. Of those, September has the fewest days with rain (8).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00158714.
When is the last frost in Williamstown?
In Williamstown, the last spring frost (32°F) comes after April 11 in half of years and after April 30 in one year in ten; the first autumn frost comes before October 29 in half of years and before October 14 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- April 111 year in 10 after April 30; 9 in 10 after March 28
- First autumn frost, half of years before
- October 291 year in 10 before October 14; 9 in 10 before November 11
NOAA puts the median frost-free season at 199 days, and the season without a hard freeze (28°F) at 222 days.
A hard freeze (28°F) comes after March 31 in half of springs and before November 8 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Williamstown in zone 6b in ZIP code 41097.
Frost dates for every NOAA station in Kentucky · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00158714; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get in Williamstown?
In a normal year in Williamstown, 23 days a year reach 90°F, 91 nights fall to 32°F or colder and 142 days bring measurable precipitation.
- Days at 90°F or more
- 23a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 91a normal year
- Days that stay below freezing
- 14high of 32°F or less
- Days with 0.01 inch of precipitation
- 142a normal year
- Days with 1 inch of snow or more
- 7a normal year
The highest temperature in this station's record (since 1902) is 110°F, on July 28, 1930; the lowest is −23°F, on January 19, 1994.
The wettest calendar year on that record is 1990, with 60.36 in; the snowiest season is 1977–78, with 48.5 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00158714; records: ACIS (NOAA Regional Climate Centers), station USC00158714. Records use complete months only; a month missing more than three days is left out.
How sunny is Williamstown?
Over a year 73% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Williamstown, 4.1 kWh per square metre a day. August is the sunniest month (81%) and December the cloudiest (60%).
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 61% | 1.9 |
| February | 62% | 2.6 |
| March | 65% | 3.7 |
| April | 72% | 5.0 |
| May | 72% | 5.5 |
| June | 79% | 6.3 |
| July | 79% | 6.0 |
| August | 81% | 5.6 |
| September | 79% | 4.6 |
| October | 73% | 3.3 |
| November | 70% | 2.4 |
| December | 60% | 1.7 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Williamstown need?
A normal year in Williamstown brings 4,392 heating degree days, 18% fewer than the median U.S. place (5,373), and 1,276 cooling degree days, 41% more than the median (908). Five months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 4,117 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 978 | 0 |
| February | 771 | 0 |
| March | 603 | 2 |
| April | 274 | 24 |
| May | 80 | 102 |
| June | 9 | 249 |
| July | 0 | 363 |
| August | 1 | 327 |
| September | 32 | 175 |
| October | 234 | 32 |
| November | 552 | 3 |
| December | 857 | 0 |
| Year (annual) | 4,392 | 1,276 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00158714. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
How does Williamstown's climate compare?
Williamstown is warmer than 38 of the other 67 places with their own NOAA record in Kentucky, and wetter than 1. Across the 7,247 U.S. stations with normals, its annual mean of 56.4°F is warmer than 65%.
In the Köppen classification computed from these normals, Williamstown is Cfa: temperate, no dry season, hot summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Williamstown share this climate record?
2 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Dry Ridge, KY2,207 people · 4 mi NW
- Corinth, KY231 people · 10 mi S
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Williamstown's climate
What is the coldest month in Williamstown?
January, with a normal high of 42°F and a normal low of 25°F. The warmest is July (87°F by day, 66°F at night).
Does it snow in Williamstown?
Yes: 16 inches in a normal year, falling on 15 days with 0.1 inch or more, the most in January (6.7 inches).
What is the rainiest month in Williamstown?
June, with 4.99 in of precipitation in a normal year; the driest is October with 3.00 in.
What plant hardiness zone is Williamstown in?
The USDA's 2023 map puts Williamstown in zone 6b in ZIP code 41097.
How late can frost come in Williamstown?
In half of years the last 32°F night comes after April 11; in one year in ten it comes after April 30. Waiting until April 30 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Kentucky climateThe statewide normals and every place in the state
- Glencoe, KY21 miles from this station, 53.0°F a year
- Cynthiana, KY23 miles from this station, 54.8°F a year
- Chilo, OH24 miles from this station, 54.9°F a year
- Warsaw, KY24 miles from this station, 55.2°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made