bellwether

The 50’s (?) era Weather Bell at the corner of Clark and Monroe. Apparently, it would change colors as a (ahem) bellwether of the weather.

When Weather Bell is emerald green
No change in temperature is foreseen.
When Weather Bell is glowing red
Warmer weather is ahead.
When Weather Bell is gleaming gold
A temperature drop is foretold
When Weather Bell is in agitation,
Prepare yourself for precipitation.