Average Weather in South Windham Connecticut, United States
In South Windham, the summers are warm, the winters are freezing, and it is partly cloudy year round. Over the course of the year, the temperature typically varies from 19°F to 82°F and is rarely below 3°F or above 90°F.
Based on the tourism score, the best time of year to visit South Windham for warm-weather activities is from mid June to mid September.
The warm season lasts for 3.5 months, from June 1 to September 16, with an average daily high temperature above 73°F. The hottest day of the year is July 21, with an average high of 82°F and low of 64°F.
The cold season lasts for 3.3 months, from December 3 to March 13, with an average daily high temperature below 45°F. The coldest day of the year is January 30, with an average low of 19°F and high of 36°F.
Average High and Low Temperature
The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.
Average Hourly Temperature
In South Windham, the average percentage of the sky covered by clouds experiences mild seasonal variation over the course of the year.
The clearer part of the year in South Windham begins around June 26 and lasts for 4.5 months, ending around November 11. On September 6, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 64% of the time, and overcast or mostly cloudy 36% of the time.
The cloudier part of the year begins around November 11 and lasts for 7.5 months, ending around June 26. On February 28, the cloudiest day of the year, the sky is overcast or mostly cloudy 54% of the time, and clear, mostly clear, or partly cloudy 46% of the time.
Cloud Cover Categories
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in South Windham varies throughout the year.
The wetter season lasts 4.7 months, from March 26 to August 17, with a greater than 28% chance of a given day being a wet day. The chance of a wet day peaks at 34% on May 31.
The drier season lasts 7.3 months, from August 17 to March 26. The smallest chance of a wet day is 23% on January 29.
Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 34% on May 31.
Daily Chance of Precipitation
To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. South Windham experiences some seasonal variation in monthly rainfall.
Rain falls throughout the year in South Windham. The most rain falls during the 31 days centered around October 12, with an average total accumulation of 3.7 inches.
The least rain falls around January 24, with an average total accumulation of 1.9 inches.
Average Monthly Rainfall
We report snowfall in liquid-equivalent terms. The actual depth of new snowfall is typically between 5 and 10 times the liquid-equivalent amount, assuming the ground is frozen. Colder, drier snow tends to be on the higher end of that range and warmer, wetter snow on the lower end.
As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. South Windham experiences significant seasonal variation in monthly liquid-equivalent snowfall.
The snowy period of the year lasts for 5.3 months, from November 6 to April 14, with a sliding 31-day liquid-equivalent snowfall of at least 0.1 inches. The most snow falls during the 31 days centered around January 26, with an average total liquid-equivalent accumulation of 1.0 inches.
The snowless period of the year lasts for 6.7 months, from April 14 to November 6. The least snow falls around July 21, with an average total liquid-equivalent accumulation of 0.0 inches.
Average Liquid-Equivalent Monthly Snowfall
The length of the day in South Windham varies significantly over the course of the year. In 2017, the shortest day is December 21, with 9 hours, 9 minutes of daylight; the longest day is June 21, with 15 hours, 12 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:13 AM on June 14, and the latest sunrise is 2 hours, 11 minutes later at 7:24 AM on November 4. The earliest sunset is at 4:18 PM on December 8, and the latest sunset is 4 hours, 9 minutes later at 8:27 PM on June 27.
Daylight saving time (DST) is observed in South Windham during 2017, starting in the spring on March 12, lasting 7.8 months, and ending in the fall on November 5.
Sunrise & Sunset with Twilight and Daylight Saving Time
South Windham experiences significant seasonal variation in the perceived humidity.
The muggier period of the year lasts for 3.5 months, from June 8 to September 23, during which time the comfort level is muggy, oppressive, or miserable at least 11% of the time. The muggiest day of the year is August 2, with muggy conditions 44% of the time.
The least muggy day of the year is February 23, when muggy conditions are essentially unheard of.
Humidity Comfort Levels
The average hourly wind speed in South Windham experiences significant seasonal variation over the course of the year.
The windier part of the year lasts for 5.9 months, from October 27 to April 24, with average wind speeds of more than 5.7 miles per hour. The windiest day of the year is February 23, with an average hourly wind speed of 7.3 miles per hour.
The calmer time of year lasts for 6.1 months, from April 24 to October 27. The calmest day of the year is August 1, with an average hourly wind speed of 4.1 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in South Windham varies throughout the year.
The wind is most often from the south for 1.9 weeks, from May 12 to May 25; for 2.3 weeks, from June 3 to June 19; for 3.0 days, from June 25 to June 28; and for 2.3 months, from July 20 to September 28, with a peak percentage of 38% on July 28. The wind is most often from the west for 1.3 weeks, from May 25 to June 3; for 6.0 days, from June 19 to June 25; for 3.1 weeks, from June 28 to July 20; and for 7.5 months, from September 28 to May 12, with a peak percentage of 39% on July 7.
South Windham is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.
The average water temperature experiences significant seasonal variation over the course of the year.
The time of year with warmer water lasts for 3.5 months, from June 26 to October 9, with an average temperature above 64°F. The day of the year with the warmest water is August 13, with an average temperature of 70°F.
The time of year with cooler water lasts for 3.6 months, from December 31 to April 19, with an average temperature below 44°F. The day of the year with the coolest water is February 25, with an average temperature of 38°F.
Average Water Temperature
Best Time of Year to Visit
To characterize how pleasant the weather is in South Windham throughout the year, we compute two travel scores.
The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best time of year to visit South Windham for general outdoor tourist activities is from mid June to mid September, with a peak score in the third week of August.
The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit South Windham for hot-weather activities is from early July to mid August, with a peak score in the last week of July.
For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.
Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.
Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.
Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.
Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.
The growing season in South Windham typically lasts for 5.6 months (171 days), from around April 27 to around October 15, rarely starting before April 10 or after May 17, and rarely ending before September 27 or after November 2.
Time Spent in Various Temperature Bands and the Growing Season
Based on growing degree days alone, the first spring blooms in South Windham should appear around April 21, only rarely appearing before April 7 or after May 2.
Growing Degree Days
The average daily incident shortwave solar energy experiences extreme seasonal variation over the course of the year.
The brighter period of the year lasts for 3.6 months, from May 2 to August 20, with an average daily incident shortwave energy per square meter above 5.8 kWh. The brightest day of the year is June 30, with an average of 6.9 kWh.
The darker period of the year lasts for 3.2 months, from November 4 to February 11, with an average daily incident shortwave energy per square meter below 2.7 kWh. The darkest day of the year is December 23, with an average of 1.7 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of South Windham are 41.680 deg latitude, -72.170 deg longitude, and 305 ft elevation.
The topography within 2 miles of South Windham contains significant variations in elevation, with a maximum elevation change of 528 feet and an average elevation above sea level of 285 feet. Within 10 miles also contains significant variations in elevation (787 feet). Within 50 miles contains significant variations in elevation (1,480 feet).
The area within 2 miles of South Windham is covered by trees (84%), within 10 miles by trees (92%), and within 50 miles by trees (59%) and water (21%).
This report illustrates the typical weather in South Windham, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.
Temperature and Dew Point
There are 4 weather stations near enough to contribute to our estimation of the temperature and dew point in South Windham.
For each station, the records are corrected for the elevation difference between that station and South Windham according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.
The estimated value at South Windham is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between South Windham and a given station.
The stations contributing to this reconstruction are: Windham Airport (85%, 7 kilometers, north); Groton-New London Airport (6%, 40 kilometers, south); Chester Airport (6%, 43 kilometers, southwest); and Theodore Francis Green State Airport (3.4%, 61 kilometers, east).
Time zones for aiports and weather stations are provided by AskGeo.com .