Weather Phenomena:
Lightning Science
In 2016, there was 677,429 lightning flashes in Illinois. How does this compare with other states? See the Cloud-to Ground Lightning Flashes By State compiled by NOAA. Also check out the Lightning Injury Research program at at the University of Illinois at Chicago:

"An informational and educational tool for survivors of lightning strike and the physicians who treat them. An educational resource for students, teachers, and the media."

-- From National Weather Service  

Weather Phenomena:
Storm and Tornado Science
Illinois prairies are prone to tornadoes and thunderstorms. The following sites pull data collected by the Storm Prediction Center run by the National Weather Service:

• UIUC Department of Atmospheric Sciences - Tornado Plots For Illinois
• Illinois State Water Survey - Tornado Maps for Each Illinois County
• Tornado History Project - Tornado maps and statistics - Illinois

-- From Storm Prediction Center  

Weather Phenomena:
Drought in Illinois
In 2017, drought is naught in the Chicagoland area. However central Illinois is caught with abnormally dry drought.
-- From Illinois State Water Survey  

Weather Phenomena:
Flood in Illinois
The rain comes down, the water rises up, and flood flashes warning. Unless you live in an Illinois flood zone, you may not know where they are:

• Cook County
• DuPage County
• Kane County
• Lake County
• Will County

To know more about flood:

• National Weather Service - Types of flooding in Illinois
• Ready Illinois - Prepare for flood hazards

-- From Illinois Flood Maps  

Weather Phenomena:
Tree House Weather Kids
Your kid turns around and asks you a weather question. You answer her and both of you can explore further about Seasons & Temperature, Air Pressure & Wind, Cloud & Moisture, and more.
-- From University of Illinois Extension  

Weather Phenomena:
Chicago Weather Averages
Looking for some trivia question for your party? Here are the averages for temperature, precipitation, snow fall, sunshine, humidity, wind and storms frequencies for Chicago in the month of
-- From Current Results Publishing  

Local Observatories:
Dearborn Observatory
Located in Evanston by the lake, this observatory is open for public observing with the historic 18.5" refracting telescope every Friday night.
-- From Northwestern University  

Local Observatories:
Doane Observatory
Located 190 feet above Lake Geneva, WI, The modern telescope allows views of the heavens from downtown Chicago, through all the light pollution from the city street lights.
-- From Adler Planetarium  

Local Observatories:
Glen D. Riley Observatory
The GDRO in Naperville houses a primary 16" Newtonian reflecting telescope designed for viewing under the Chicagoland skies.
-- From Naperville Astronomical Association  

Local Observatories:
University of Illinois Observatory
Built in 1896, the observatory was designated a National Historic Landmark in 1989. The observatory still contains a 12" Brashear refractor, although it is not used for professional research.
-- From University of Illinois  

Local Observatories:
Yerkes Observatory
Located 190 feet above Lake Geneva, WI, Yerkes Observatory is a research branch of the Department of Astronomy and Astrophysics of the University of Chicago. This department also supports the Ryerson Astronomical Society which maintains a 100-year telescope.
-- From University of Chicago  

Local Observatories:
Clear Sky Clocks in Illinois
For amateur astronomers, the Clear Sky Clocks can "forecast clear skies for specific locations for up to two days".
-- From ClearDarkSky