The Brief Chicago enjoyed sunny skies and comfortable temperatures in the upper 70s and low 80s Wednesday. Lollapalooza starts Thursday with warm weather, but rain could impact Friday and Saturday events. Sunny skies will become partly cloudy in the afternoon with highs in the upper 80s. High temperatures will be in the upper 70s to low 80s on Friday and then mid to upper 70s on Saturday. Sunshine returns on Sunday with highs in the upper 70s.