Monday's forecast for Chicago:
Rain showers early, becoming a steady, soaking rain later in the day with a few rumbles of thunder possible. High 62F. Winds SSE at 10 to 20 mph. Chance of rain 70%.
Evening: Showers and thundershowers likely. Low near 55F. Winds SSE at 10 to 15 mph. Chance of rain 80%. Rainfall around a quarter of an inch.
We'll need waterproof armbands and signs.