Clear Sky Clocks
Forecast colors key

Cloud Cover:

Transparency:

Seeing:

Darkness
(limiting magnitude, not counting any manmade light pollution effects):

Wind:

Humidity
(ground level R.H.):

Cloud modeling forecasts
for our Astronomy Education Center:

for our CF dark site area:

and for our RR dark site area:

The cloud/tran data for downtown Chicago, Ill., same time scale as above clocks:

And for Hennepin Canal Parkway State Park, near Princeton, Ill.:

And for Green River State Park, near Harmon, Ill.:

Click any Clear Sky Clock above for interpretive info and interactive versions.

NOAA's experimental cloud cover graphical forecast for:
7:00 10:00 1:00 7:00

NOAA's predicted high
temperatures for today
 

NOAA's predicted chance
of precipitation
for next 12 hours