Monday is going to start and end very similarly with temperatures in the 40s!  A nice warm-up should occur by the late morning into the afternoon with temperatures climbing into the low to middle 60s.  It's all about the winds on Monday.  Those winds will start westerly, but then they will quickly change late in the day.

Those winds are expected to shift to the northeast after Noon, and that will quickly drop temperatures into the 40s, especially along the lake.

There is a chance that some spots could drop enough in an hour for it to be considered a "pneumonia front"  This type of front is enhanced by cold lake waters during the spring across the Great lakes.  You need a temperature drop of 16 degrees in an hour for it to qualify.

I would have your jacket with you as you are out and about Monday afternoon into the evening!  That quick drop in temperature might catch you by surprise.