Average Weather in Glendale Heights Illinois, United States
In Glendale Heights, the summers are warm and wet, the winters are freezing and windy, and it is partly cloudy year round. Over the course of the year, the temperature typically varies from 17°F to 84°F and is rarely below -3°F or above 92°F.
Based on the tourism score, the best time of year to visit Glendale Heights for warm-weather activities is from mid June to mid September.
The warm season lasts for 3.8 months, from May 24 to September 19, with an average daily high temperature above 73°F. The hottest day of the year is July 19, with an average high of 84°F and low of 66°F.
The cold season lasts for 3.1 months, from December 1 to March 3, with an average daily high temperature below 41°F. The coldest day of the year is January 22, with an average low of 17°F and high of 30°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 Glendale Heights, 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 Glendale Heights begins around June 13 and lasts for 4.4 months, ending around October 25. On August 26, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 68% of the time, and overcast or mostly cloudy 32% of the time.
The cloudier part of the year begins around October 25 and lasts for 7.6 months, ending around June 13. On December 29, the cloudiest day of the year, the sky is overcast or mostly cloudy 58% of the time, and clear, mostly clear, or partly cloudy 42% 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 Glendale Heights varies throughout the year.
The wetter season lasts 6.3 months, from March 28 to October 5, with a greater than 26% chance of a given day being a wet day. The chance of a wet day peaks at 37% on May 24.
The drier season lasts 5.7 months, from October 5 to March 28. The smallest chance of a wet day is 14% 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 in Glendale Heights changes throughout the year.
Rain alone is the most common for 11 months, from February 7 to January 19. The highest chance of a day with rain alone is 37% on May 24.
Snow alone is the most common for 2.7 weeks, from January 19 to February 7. The highest chance of a day with snow alone is 7% on February 1.
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. Glendale Heights experiences significant seasonal variation in monthly rainfall.
Rain falls throughout the year in Glendale Heights. The most rain falls during the 31 days centered around June 2, with an average total accumulation of 3.8 inches.
The least rain falls around January 27, with an average total accumulation of 0.7 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. Glendale Heights experiences some seasonal variation in monthly liquid-equivalent snowfall.
The snowy period of the year lasts for 4.5 months, from November 16 to March 30, with a sliding 31-day liquid-equivalent snowfall of at least 0.1 inches. The most snow falls during the 31 days centered around February 2, with an average total liquid-equivalent accumulation of 0.4 inches.
The snowless period of the year lasts for 7.5 months, from March 30 to November 16. The least snow falls around July 24, with an average total liquid-equivalent accumulation of 0.0 inches.
Average Liquid-Equivalent Monthly Snowfall
The length of the day in Glendale Heights varies significantly over the course of the year. In 2018, the shortest day is December 21, with 9 hours, 8 minutes of daylight; the longest day is June 21, with 15 hours, 14 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:16 AM on June 15, and the latest sunrise is 2 hours, 11 minutes later at 7:27 AM on November 3. The earliest sunset is at 4:21 PM on December 7, and the latest sunset is 4 hours, 11 minutes later at 8:31 PM on June 27.
Daylight saving time (DST) is observed in Glendale Heights during 2018, starting in the spring on March 11, lasting 7.8 months, and ending in the fall on November 4.
Sunrise & Sunset with Twilight and Daylight Saving Time
Glendale Heights experiences significant seasonal variation in the perceived humidity.
The muggier period of the year lasts for 3.7 months, from May 29 to September 20, during which time the comfort level is muggy, oppressive, or miserable at least 10% of the time. The muggiest day of the year is July 27, with muggy conditions 41% of the time.
The least muggy day of the year is February 4, when muggy conditions are essentially unheard of.
Humidity Comfort Levels
The average hourly wind speed in Glendale Heights experiences significant seasonal variation over the course of the year.
The windier part of the year lasts for 7.7 months, from October 3 to May 26, with average wind speeds of more than 10.4 miles per hour. The windiest day of the year is January 15, with an average hourly wind speed of 12.8 miles per hour.
The calmer time of year lasts for 4.3 months, from May 26 to October 3. The calmest day of the year is August 3, with an average hourly wind speed of 7.9 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in Glendale Heights varies throughout the year.
The wind is most often from the north for 1.5 months, from March 6 to April 21, with a peak percentage of 29% on March 8. The wind is most often from the south for 2.4 months, from April 24 to July 5 and for 3.5 months, from July 31 to November 15, with a peak percentage of 36% on September 7. The wind is most often from the west for 3.7 weeks, from July 5 to July 31 and for 3.7 months, from November 15 to March 6, with a peak percentage of 31% on July 12.
Glendale Heights 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 2.7 months, from July 4 to September 25, with an average temperature above 65°F. The day of the year with the warmest water is August 11, with an average temperature of 72°F.
The time of year with cooler water lasts for 4.9 months, from December 12 to May 10, with an average temperature below 43°F. The day of the year with the coolest water is March 1, with an average temperature of 35°F.
Average Water Temperature
Best Time of Year to Visit
To characterize how pleasant the weather is in Glendale Heights 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 Glendale Heights for general outdoor tourist activities is from mid June to mid September, with a peak score in the last 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 Glendale Heights for hot-weather activities is from late June to late August, with a peak score in the third 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 Glendale Heights typically lasts for 5.9 months (178 days), from around April 19 to around October 14, rarely starting before April 1 or after May 8, and rarely ending before September 26 or after November 3.
Time Spent in Various Temperature Bands and the Growing Season
Based on growing degree days alone, the first spring blooms in Glendale Heights should appear around April 13, only rarely appearing before March 29 or after April 27.
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 3.5 months, from May 5 to August 21, with an average daily incident shortwave energy per square meter above 5.9 kWh. The brightest day of the year is July 1, with an average of 6.9 kWh.
The darker period of the year lasts for 3.3 months, from November 2 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 21, with an average of 1.7 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Glendale Heights are 41.910 deg latitude, -88.072 deg longitude, and 751 ft elevation.
The topography within 2 miles of Glendale Heights contains only modest variations in elevation, with a maximum elevation change of 135 feet and an average elevation above sea level of 755 feet. Within 10 miles also contains only modest variations in elevation (479 feet). Within 50 miles contains only modest variations in elevation (768 feet).
The area within 2 miles of Glendale Heights is covered by artificial surfaces (100%), within 10 miles by artificial surfaces (89%), and within 50 miles by cropland (44%) and artificial surfaces (29%).
This report illustrates the typical weather in Glendale Heights, 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 Glendale Heights.
For each station, the records are corrected for the elevation difference between that station and Glendale Heights 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 Glendale Heights is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Glendale Heights and a given station.
The stations contributing to this reconstruction are: DuPage County Airport (39%, 14 kilometers, west); Chicago O'Hare International Airport (37%, 15 kilometers, northeast); Chicago Midway International Airport (13%, 30 kilometers, southeast); and Lewis University Airport (11%, 34 kilometers, south).
Time zones for aiports and weather stations are provided by AskGeo.com .