I would look for a loose connection behind the kick panel under steering column on driver's side. Do your brake lights always work? The switch on the brake pedal and some steering column wiring might run together. If someone worked under there before maybe they did not reseat a connector well. I had such after replacing an a/c evaporator - many unrelated symptoms appeared together and I had not pushed in one of the big connectors fully when reinstalling.

The hot weather connection is that marginal electrical connections may act up in heat because electrical resistance increases with temperature.

Another possibility many have reported as causing seemingly unrelated symptoms to occur together is a failing ignition switch.