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May Weather in Crystal Lake Illinois, United States

Daily high temperatures increase by 10°F, from 65°F to 75°F, rarely falling below 52°F or exceeding 87°F.

Daily low temperatures increase by 10°F, from 44°F to 54°F, rarely falling below 34°F or exceeding 65°F.

For reference, on July 18, the hottest day of the year, temperatures in Crystal Lake typically range from 64°F to 83°F, while on January 22, the coldest day of the year, they range from 15°F to 29°F.

Average High and Low Temperature in May in Crystal Lake

The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.

The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on May. The horizontal axis is the day, 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 May in Crystal Lake

Average Hourly Temperature in May in Crystal LakeMay112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AMAprJunvery coldvery coldcoldcoolcomfortablewarmcomfortable
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The average hourly temperature, color coded into bands. The shaded overlays indicate night and civil twilight.

Garrni, Armenia (6,040 miles away) is the far-away foreign place with temperatures most similar to Crystal Lake (view comparison).

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The month of May in Crystal Lake experiences gradually decreasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy decreasing from 52% to 47%.

The clearest day of the month is May 30, with clear, mostly clear, or partly cloudy conditions 53% of the time.

For reference, on December 30, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 58%, while on August 25, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 68%.

Cloud Cover Categories in May in Crystal Lake

Cloud Cover Categories in May in Crystal LakeMay11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%AprJunMay 148%May 148%May 3153%May 3153%May 1149%May 1149%May 2151%May 2151%clearmostly clearpartly cloudymostly cloudyovercast
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Crystal Lake, the chance of a wet day over the course of May is rapidly increasing, starting the month at 31% and ending it at 38%.

For reference, the year's highest daily chance of a wet day is 38% on May 23, and its lowest chance is 14% on February 2.

Probability of Precipitation in May in Crystal Lake

Probability of Precipitation in May in Crystal LakeMay11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%0%5%5%10%10%15%15%20%20%25%25%30%30%35%35%40%40%AprJunMay 2338%May 2338%May 131%May 131%May 1134%May 1134%rainmixed
The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).

Rainfall

To show variation within the month and not just the monthly total, we show the rainfall accumulated over a sliding 31-day period centered around each day.

The average sliding 31-day rainfall during May in Crystal Lake is increasing, starting the month at 3.2 inches, when it rarely exceeds 5.1 inches or falls below 1.3 inches, and ending the month at 3.8 inches, when it rarely exceeds 6.2 inches or falls below 1.6 inches.

Average Monthly Rainfall in May in Crystal Lake

The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average snowfall.

Over the course of May in Crystal Lake, the length of the day is increasing. From the start to the end of the month, the length of the day increases by 58 minutes, implying an average daily increase of 1 minute, 56 seconds, and weekly increase of 13 minutes, 31 seconds.

The shortest day of the month is May 1, with 14 hours, 5 minutes of daylight and the longest day is May 31, with 15 hours, 3 minutes of daylight.

Hours of Daylight and Twilight in May in Crystal Lake

The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.

The latest sunrise of the month in Crystal Lake is 5:47 AM on May 1 and the earliest sunrise is 28 minutes earlier at 5:19 AM on May 31.

The earliest sunset is 7:53 PM on May 1 and the latest sunset is 30 minutes later at 8:22 PM on May 31.

Daylight saving time is observed in Crystal Lake during 2024, but it neither starts nor ends during May, so the entire month is in daylight saving time.

For reference, on June 20, the longest day of the year, the Sun rises at 5:16 AM and sets 15 hours, 16 minutes later, at 8:33 PM, while on December 21, the shortest day of the year, it rises at 7:19 AM and sets 9 hours, 5 minutes later, at 4:24 PM.

Sunrise & Sunset with Twilight in May in Crystal Lake

The solar day over the course of May. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray.

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.

Solar Elevation and Azimuth in May in Crystal Lake

Solar Elevation and Azimuth in May in Crystal LakeMay112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AMAprJun0010102020203030404050505060600001010202030303040405050606070
northeastsouthwest
Solar elevation and azimuth over the course of May 2024. The black lines are lines of constant solar elevation (the angle of the sun above the horizon, in degrees). The background color fills indicate the azimuth (the compass bearing) of the sun. The lightly tinted areas at the boundaries of the cardinal compass points indicate the implied intermediate directions (northeast, southeast, southwest, and northwest).

The figure below presents a compact representation of key lunar data for May 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. The label associated with each bar indicates the date and time that the phase is obtained, and the companion time labels indicate the rise and set times of the Moon for the nearest time interval in which the moon is above the horizon.

Moon Rise, Set & Phases in May in Crystal Lake

Moon Rise, Set & Phases in May in Crystal LakeMay112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM12 AM4 AM4 AM8 AM8 AM12 PM12 PM4 PM4 PM8 PM8 PM12 AM12 AMAprJunApr 81:22 PMApr 81:22 PMApr 236:50 PMApr 236:50 PMMay 710:23 PMMay 710:23 PMMay 238:54 AMMay 238:54 AMJun 67:38 AMJun 67:38 AMJun 218:09 PMJun 218:09 PM6:18 AM6:18 AM7:43 PM7:43 PM7:45 PM7:45 PM6:05 AM6:05 AM5:08 AM5:08 AM7:55 PM7:55 PM7:48 PM7:48 PM5:03 AM5:03 AM4:53 AM4:53 AM9:18 PM9:18 PM8:54 PM8:54 PM5:20 AM5:20 AM
The time in which the moon is above the horizon (light blue area), with new moons (dark gray lines) and full moons (blue lines) indicated. The shaded overlays indicate night and civil twilight.
May 2024IlluminationMoonriseMoonsetMoonriseMeridian PassingDistance
1
50%2:35 AMESE12:07 PMWSW-7:21 AMS232,073 mi
2
38%3:06 AMESE1:24 PMWSW-8:15 AMS229,753 mi
3
27%3:32 AMESE2:41 PMWSW-9:06 AMS227,781 mi
4
17%3:56 AME3:58 PMW-9:55 AMS226,360 mi
5
9%4:18 AME5:16 PMW-10:44 AMS225,690 mi
6
3%4:42 AMENE6:35 PMWNW-11:34 AMS225,925 mi
7
0%5:08 AMENE7:55 PMWNW-12:26 PMS227,133 mi
8
1%5:39 AMENE9:15 PMWNW-1:21 PMS229,270 mi
9
4%6:17 AMNE10:30 PMNW-2:19 PMS232,180 mi
10
9%7:04 AMNE11:36 PMNW-3:19 PMS235,607 mi
11
17%8:00 AMNE--4:17 PMS239,240 mi
12
26%-12:31 AMNW9:04 AMNE5:13 PMS242,766 mi
13
35%-1:13 AMNW10:11 AMNE6:04 PMS245,905 mi
14
45%-1:46 AMWNW11:18 AMENE6:50 PMS248,444 mi
15
50%-2:13 AMWNW12:24 PMENE7:33 PMS250,240 mi
16
65%-2:35 AMWNW1:26 PMENE8:13 PMS251,226 mi
17
74%-2:54 AMW2:28 PME8:52 PMS251,401 mi
18
82%-3:11 AMW3:29 PME9:30 PMS250,826 mi
19
89%-3:29 AMW4:30 PME10:10 PMS249,606 mi
20
94%-3:47 AMWSW5:33 PMESE10:51 PMS247,881 mi
21
98%-4:08 AMWSW6:39 PMESE11:36 PMS245,803 mi
22
99%-4:33 AMWSW7:48 PMESE--
23
100%-5:03 AMWSW8:57 PMSE12:26 AMS243,530 mi
24
99%-5:42 AMSW10:04 PMSE1:19 AMS241,202 mi
25
97%-6:31 AMSW11:05 PMSE2:18 AMS238,935 mi
26
92%-7:32 AMSW11:55 PMSE3:18 AMS236,810 mi
27
84%-8:42 AMSW-4:19 AMS234,874 mi
28
75%12:36 AMESE9:57 AMWSW-5:17 AMS233,150 mi
29
64%1:09 AMESE11:14 AMWSW-6:11 AMS231,649 mi
30
50%1:36 AMESE12:29 PMWSW-7:02 AMS230,396 mi
31
41%2:00 AME1:44 PMW-7:50 AMS229,441 mi

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.

The chance that a given day will be muggy in Crystal Lake is increasing during May, rising from 1% to 11% over the course of the month.

For reference, on July 21, the muggiest day of the year, there are muggy conditions 40% of the time, while on January 1, the least muggy day of the year, there are muggy conditions 0% of the time.

Humidity Comfort Levels in May in Crystal Lake

Humidity Comfort Levels in May in Crystal LakeMay11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%AprJunMay 11%May 11%May 3111%May 3111%May 113%May 113%May 216%May 216%muggymuggyhumidhumidcomfortablecomfortabledrydryoppressiveoppressive
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
The percentage of time spent at various humidity comfort levels, categorized by dew point.

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 Crystal Lake is decreasing during May, decreasing from 11.6 miles per hour to 9.9 miles per hour over the course of the month.

For reference, on January 15, the windiest day of the year, the daily average wind speed is 12.7 miles per hour, while on August 2, the calmest day of the year, the daily average wind speed is 7.9 miles per hour.

Average Wind Speed in May in Crystal Lake

The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The hourly average wind direction in Crystal Lake throughout May is predominantly from the south, with a peak proportion of 29% on May 30.

Wind Direction in May in Crystal Lake

Wind Direction in May in Crystal LakeNESMay11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%20%80%40%60%60%40%80%20%100%0%AprJunwestsoutheastnorth
northeastsouthwest
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions, excluding hours in which the mean wind speed is less than 1.0 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Crystal Lake 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 surface water temperature in Crystal Lake is rapidly increasing during May, rising by 8°F, from 40°F to 48°F, over the course of the month.

Average Water Temperature in May in Crystal Lake

Average Water Temperature in May in Crystal LakeMay112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313130°F30°F35°F35°F40°F40°F45°F45°F50°F50°F55°F55°F60°F60°F65°F65°F70°F70°FAprJunMay 140°FMay 140°FMay 3148°FMay 3148°FMay 1142°FMay 1142°FMay 2145°FMay 2145°F
The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.

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 Crystal Lake typically lasts for 5.5 months (168 days), from around April 26 to around October 11, rarely starting before April 8 or after May 14, and rarely ending before September 23 or after October 28.

The month of May in Crystal Lake is more likely than not fully within the growing season, with the chance that a given day is in the growing season rapidly increasing from 64% to 100% over the course of the month.

Time Spent in Various Temperature Bands and the Growing Season in May in Crystal Lake

Time Spent in Various Temperature Bands and the Growing Season in May in Crystal Lakegrowing seasonMay11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%AprJun64%May 164%May 1100%May 31100%May 3187%May 1187%May 1196%May 2196%May 21Apr 810%Apr 810%freezingvery coldcoldcoolcomfortablewarmhot
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The percentage of time spent in various temperature bands. The black line is the percentage chance that a given day is within the growing season.

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.

The average accumulated growing degree days in Crystal Lake are increasing during May, increasing by 311°F, from 171°F to 482°F, over the course of the month.

Growing Degree Days in May in Crystal Lake

The average growing degree days accumulated over the course of May, with 25th to 75th and 10th to 90th percentile bands.

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 in Crystal Lake is gradually increasing during May, rising by 0.7 kWh, from 5.8 kWh to 6.5 kWh, over the course of the month.

Average Daily Incident Shortwave Solar Energy in May in Crystal Lake

Average Daily Incident Shortwave Solar Energy in May in Crystal LakeMay11223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWh8 kWh8 kWh9 kWh9 kWhAprJunMay 15.8 kWhMay 15.8 kWhMay 316.5 kWhMay 316.5 kWhMay 116.1 kWhMay 116.1 kWhMay 216.3 kWhMay 216.3 kWh
The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

For the purposes of this report, the geographical coordinates of Crystal Lake are 42.241 deg latitude, -88.316 deg longitude, and 912 ft elevation.

The topography within 2 miles of Crystal Lake contains only modest variations in elevation, with a maximum elevation change of 135 feet and an average elevation above sea level of 901 feet. Within 10 miles also contains only modest variations in elevation (308 feet). Within 50 miles contains only modest variations in elevation (745 feet).

The area within 2 miles of Crystal Lake is covered by artificial surfaces (80%) and trees (11%), within 10 miles by cropland (41%) and artificial surfaces (36%), and within 50 miles by cropland (51%) and artificial surfaces (25%).

This report illustrates the typical weather in Crystal Lake, 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 6 weather stations near enough to contribute to our estimation of the temperature and dew point in Crystal Lake.

For each station, the records are corrected for the elevation difference between that station and Crystal Lake 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 Crystal Lake is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Crystal Lake 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 Crystal Lake 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 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.

Disclaimer

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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