Climate and Average Weather Year Round in Edwardsville Illinois, United States
In Edwardsville, the summers are warm and muggy; 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 24°F to 88°F and is rarely below 8°F or above 95°F.
Based on the tourism score, the best time of year to visit Edwardsville for warm-weather activities is from late May to late September.
Average Temperature in Edwardsville
The hot season lasts for 3.9 months, from May 25 to September 20, with an average daily high temperature above 78°F. The hottest month of the year in Edwardsville is July, with an average high of 88°F and low of 68°F.
The cold season lasts for 3.0 months, from November 29 to February 28, with an average daily high temperature below 49°F. The coldest month of the year in Edwardsville is January, with an average low of 24°F and high of 40°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.
Mahdishahr, Iran (6,788 miles away) is the far-away foreign place with temperatures most similar to Edwardsville (view comparison).
In Edwardsville, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.
The clearer part of the year in Edwardsville begins around June 14 and lasts for 4.5 months, ending around October 29.
The clearest month of the year in Edwardsville is August, during which on average the sky is clear, mostly clear, or partly cloudy 69% of the time.
The cloudier part of the year begins around October 29 and lasts for 7.5 months, ending around June 14.
The cloudiest month of the year in Edwardsville is February, during which on average the sky is overcast or mostly cloudy 53% of the time.
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Edwardsville varies throughout the year.
The wetter season lasts 5.3 months, from March 23 to August 31, with a greater than 28% chance of a given day being a wet day. The month with the most wet days in Edwardsville is May, with an average of 12.0 days with at least 0.04 inches of precipitation.
The drier season lasts 6.7 months, from August 31 to March 23. The month with the fewest wet days in Edwardsville is January, with an average of 5.2 days with at least 0.04 inches of precipitation.
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 Edwardsville is May, with an average of 12.0 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 40% on June 7.
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. Edwardsville experiences significant seasonal variation in monthly rainfall.
Rain falls throughout the year in Edwardsville. The month with the most rain in Edwardsville is May, with an average rainfall of 4.1 inches.
The month with the least rain in Edwardsville is January, with an average rainfall of 1.6 inches.
As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. Edwardsville experiences some seasonal variation in monthly snowfall.
The snowy period of the year lasts for 3.6 months, from November 29 to March 16, with a sliding 31-day snowfall of at least 1.0 inches. The month with the most snow in Edwardsville is January, with an average snowfall of 3.5 inches.
The snowless period of the year lasts for 8.4 months, from March 16 to November 29. The least snow falls around July 24, with an average total accumulation of 0.0 inches.
The length of the day in Edwardsville varies significantly over the course of the year. In 2023, the shortest day is December 21, with 9 hours, 27 minutes of daylight; the longest day is June 21, with 14 hours, 53 minutes of daylight.
The earliest sunrise is at 5:34 AM on June 14, and the latest sunrise is 1 hour, 56 minutes later at 7:29 AM on November 4. The earliest sunset is at 4:37 PM on December 8, and the latest sunset is 3 hours, 51 minutes later at 8:29 PM on June 28.
Daylight saving time (DST) is observed in Edwardsville during 2023, starting in the spring on March 12, lasting 7.8 months, and ending in the fall on November 5.
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.
The figure below presents a compact representation of key lunar data for 2023. 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.
We 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.
Edwardsville experiences extreme seasonal variation in the perceived humidity.
The muggier period of the year lasts for 4.2 months, from May 18 to September 24, during which time the comfort level is muggy, oppressive, or miserable at least 18% of the time. The month with the most muggy days in Edwardsville is July, with 21.3 days that are muggy or worse.
The month with the fewest muggy days in Edwardsville is January, with 0.0 days that are muggy or worse.
This 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 Edwardsville experiences significant seasonal variation over the course of the year.
The windier part of the year lasts for 7.3 months, from October 11 to May 21, with average wind speeds of more than 8.8 miles per hour. The windiest month of the year in Edwardsville is March, with an average hourly wind speed of 11.0 miles per hour.
The calmer time of year lasts for 4.7 months, from May 21 to October 11. The calmest month of the year in Edwardsville is August, with an average hourly wind speed of 6.6 miles per hour.
The predominant average hourly wind direction in Edwardsville varies throughout the year.
The wind is most often from the south for 2.0 weeks, from February 19 to March 5 and for 9.4 months, from March 12 to December 23, with a peak percentage of 43% on June 22. The wind is most often from the north for 1.0 weeks, from March 5 to March 12, with a peak percentage of 30% on March 8. The wind is most often from the west for 1.9 months, from December 23 to February 19, with a peak percentage of 33% on January 1.
Best Time of Year to Visit
To characterize how pleasant the weather is in Edwardsville 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 Edwardsville for general outdoor tourist activities is from late May to late September, with a peak score in the last week of August.
Tourism Score in Edwardsville
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 Edwardsville for hot-weather activities is from mid June to late August, with a peak score in the last week of July.
Beach/Pool Score in Edwardsville
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.
Definitions 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 Edwardsville typically lasts for 6.7 months (205 days), from around April 5 to around October 27, rarely starting before March 17 or after April 22, and rarely ending before October 8 or after November 14.
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 Edwardsville should appear around March 20, only rarely appearing before March 6 or after April 6.
This 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 significant seasonal variation over the course of the year.
The brighter period of the year lasts for 4.1 months, from April 26 to August 29, with an average daily incident shortwave energy per square meter above 5.9 kWh. The brightest month of the year in Edwardsville is July, with an average of 6.7 kWh.
The darker period of the year lasts for 3.1 months, from November 6 to February 9, with an average daily incident shortwave energy per square meter below 3.0 kWh. The darkest month of the year in Edwardsville is December, with an average of 2.1 kWh.
For the purposes of this report, the geographical coordinates of Edwardsville are 38.811 deg latitude, -89.953 deg longitude, and 538 ft elevation.
The topography within 2 miles of Edwardsville contains only modest variations in elevation, with a maximum elevation change of 157 feet and an average elevation above sea level of 510 feet. Within 10 miles also contains only modest variations in elevation (210 feet). Within 50 miles contains only modest variations in elevation (715 feet).
The area within 2 miles of Edwardsville is covered by artificial surfaces (41%), trees (38%), and cropland (22%), within 10 miles by cropland (65%) and artificial surfaces (20%), and within 50 miles by cropland (66%) and trees (19%).
This report illustrates the typical weather in Edwardsville, 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 Edwardsville.
For each station, the records are corrected for the elevation difference between that station and Edwardsville 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 Edwardsville is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Edwardsville 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 Edwardsville 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.
All 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.
The 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.
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