Climate and Average Weather Year Round in Westerly United StatesIn Westerly, the summers are warm and humid; the winters are very cold, snowy, and windy; and it is partly cloudy year round. Over the course of the year, the temperature typically varies from 22°F to 81°F and is rarely below 7°F or above 88°F. Based on the tourism score, the best time of year to visit Westerly for warm-weather activities is from mid June to mid September. Average Temperature in WesterlyThe warm season lasts for 3.3 months, from June 5 to September 16, with an average daily high temperature above 72°F. The hottest month of the year in Westerly is July, with an average high of 80°F and low of 64°F. The cold season lasts for 3.3 months, from December 5 to March 15, with an average daily high temperature below 46°F. The coldest month of the year in Westerly is January, with an average low of 23°F and high of 38°F.
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. Qusar, Azerbaijan (5,613 miles away) and Saku, Japan (6,750 miles) are the far-away foreign places with temperatures most similar to Westerly (view comparison). CloudsIn Westerly, 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 Westerly begins around June 26 and lasts for 4.5 months, ending around November 11. The clearest month of the year in Westerly is September, during which on average the sky is clear, mostly clear, or partly cloudy 63% of the time. The cloudier part of the year begins around November 11 and lasts for 7.5 months, ending around June 26. The cloudiest month of the year in Westerly is February, during which on average the sky is overcast or mostly cloudy 52% of the time.
PrecipitationWesterly does not experience significant seasonal variation in the frequency of wet days (i.e., those with greater than 0.04 inches of liquid or liquid-equivalent precipitation). The frequency ranges from 23% to 32%, with an average value of 27%. Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. The month with the most days of rain alone in Westerly is May, with an average of 9.2 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 32% on May 30.
RainfallTo 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. Westerly experiences some seasonal variation in monthly rainfall. Rain falls throughout the year in Westerly. The month with the most rain in Westerly is April, with an average rainfall of 3.7 inches. The month with the least rain in Westerly is January, with an average rainfall of 2.3 inches.
SnowfallAs with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. Westerly experiences significant seasonal variation in monthly snowfall. The snowy period of the year lasts for 4.8 months, from November 14 to April 6, with a sliding 31-day snowfall of at least 1.0 inches. The month with the most snow in Westerly is January, with an average snowfall of 7.1 inches. The snowless period of the year lasts for 7.2 months, from April 6 to November 14. The least snow falls around July 18, with an average total accumulation of 0.0 inches.
SunThe length of the day in Westerly varies significantly over the course of the year. In 2024, the shortest day is December 21, with 9 hours, 11 minutes of daylight; the longest day is June 20, with 15 hours, 10 minutes of daylight.
The earliest sunrise is at 5:13 AM on June 13, and the latest sunrise is 2 hours, 7 minutes later at 7:20 AM on November 2. The earliest sunset is at 4:17 PM on December 7, and the latest sunset is 4 hours, 7 minutes later at 8:24 PM on June 27. Daylight saving time (DST) is observed in Westerly during 2024, starting in the spring on March 10, lasting 7.8 months, and ending in the fall on November 3. The figure below presents a compact representation of the sun's elevation (the angle of the sun above the horizon) and azimuth (its compass bearing) for every hour of every day in the reporting period. The horizontal axis is the day of the year and the vertical axis is the hour of the day. For a given day and hour of that day, the background color indicates the azimuth of the sun at that moment. The black isolines are contours of constant solar elevation. MoonThe figure below presents a compact representation of key lunar data for 2024. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases. HumidityWe base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night. Westerly experiences extreme seasonal variation in the perceived humidity. The muggier period of the year lasts for 3.3 months, from June 14 to September 24, during which time the comfort level is muggy, oppressive, or miserable at least 13% of the time. The month with the most muggy days in Westerly is July, with 13.8 days that are muggy or worse. The least muggy day of the year is February 28, when muggy conditions are essentially unheard of.
WindThis section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages. The average hourly wind speed in Westerly experiences significant seasonal variation over the course of the year. The windier part of the year lasts for 6.2 months, from October 13 to April 18, with average wind speeds of more than 8.0 miles per hour. The windiest month of the year in Westerly is January, with an average hourly wind speed of 10.2 miles per hour. The calmer time of year lasts for 5.8 months, from April 18 to October 13. The calmest month of the year in Westerly is July, with an average hourly wind speed of 5.8 miles per hour.
The predominant average hourly wind direction in Westerly varies throughout the year. The wind is most often from the south for 3.3 months, from June 11 to September 21, with a peak percentage of 41% on July 27. The wind is most often from the west for 8.7 months, from September 21 to June 11, with a peak percentage of 47% on January 1. Water TemperatureWesterly 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 3.4 months, from June 26 to October 6, with an average temperature above 63°F. The month of the year in Westerly with the warmest water is August, with an average temperature of 69°F. The time of year with cooler water lasts for 3.7 months, from December 31 to April 21, with an average temperature below 45°F. The month of the year in Westerly with the coolest water is February, with an average temperature of 39°F.
Best Time of Year to VisitTo characterize how pleasant the weather is in Westerly 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 Westerly for general outdoor tourist activities is from mid June to mid September, with a peak score in the last week of August. Tourism Score in WesterlyThe 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 Westerly for hot-weather activities is from early July to mid August, with a peak score in the third week of July. Beach/Pool Score in WesterlyMethodologyFor 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. Growing SeasonDefinitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere). The growing season in Westerly typically lasts for 6.3 months (191 days), from around April 13 to around October 21, rarely starting before March 26 or after May 1, and rarely ending before October 3 or after November 9. Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F. Based on growing degree days alone, the first spring blooms in Westerly should appear around April 30, only rarely appearing before April 18 or after May 11. Solar EnergyThis section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation. 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 3.5 months, from May 1 to August 18, with an average daily incident shortwave energy per square meter above 5.9 kWh. The brightest month of the year in Westerly is June, with an average of 6.8 kWh. The darker period of the year lasts for 3.3 months, from November 3 to February 12, with an average daily incident shortwave energy per square meter below 2.8 kWh. The darkest month of the year in Westerly is December, with an average of 1.8 kWh.
TopographyFor the purposes of this report, the geographical coordinates of Westerly are 41.378 deg latitude, -71.827 deg longitude, and 30 ft elevation. The topography within 2 miles of Westerly contains only modest variations in elevation, with a maximum elevation change of 210 feet and an average elevation above sea level of 69 feet. Within 10 miles contains only modest variations in elevation (522 feet). Within 50 miles contains significant variations in elevation (1,302 feet). The area within 2 miles of Westerly is covered by artificial surfaces (57%) and trees (35%), within 10 miles by trees (58%) and water (32%), and within 50 miles by water (50%) and trees (39%). Data SourcesThis report illustrates the typical weather in Westerly, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016. Temperature and Dew PointThere are 4 weather stations near enough to contribute to our estimation of the temperature and dew point in Westerly. For each station, the records are corrected for the elevation difference between that station and Westerly 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 Westerly is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Westerly and a given station. The stations contributing to this reconstruction are:
To get a sense of how much these sources agree with each other, you can view a comparison of Westerly and the stations that contribute to our estimates of its temperature history and climate. Please note that each source's contribution is adjusted for elevation and the relative change present in the MERRA-2 data. Other DataAll data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Algorithms 2nd Edition , by Jean Meeus. All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid. Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations. Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory. Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database . Time zones for airports and weather stations are provided by AskGeo.com . Maps are © OpenStreetMap contributors. DisclaimerThe information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site. We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands. We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader. Please review our full terms contained on our Terms of Service page. |