Last time I was in this situation, there was a storm blowing through ORD and I was connecting from CMH to YVR. I switched to CMH-DEN-YVR. The weather in DEN was great, but the DEN-YVR flight was delayed over three hours due to crew availability. We would up arriving hours after the slightly delayed ORD-YVR flight.

Sometimes one can outsmart oneself in making changes to avoid wx.