Attilla Danko maintains the
Clear Dark Sky Clock
which is, in his own words,
"an attempt to show at a glance when, in the next 48 hours, we might
expect clear and dark skies for one of many observing sites." Here's
one for Lincolnshire IL (near Riverwoods):
The North-Central Region of the Astronomical League (NCRAL) provides a newsletter, Northern Lights. Click on the Newsletter Archive link of the NCRAL Welcome page.