Sharing my recent experiences here, for the record. I was having intermittent overheating issues usually traveling uphill or when stopped in traffic so I went through the entire cooling system eventually replacing the water pump, thermostat, radiator and all hoses, and the fan clutch assembly. My problem persisted. Driving up a hill, the temperature gauge would climb from below the half-way point to just shy of the H line...

I ended up finally replacing the engine coolant temperature sensor and haven't had the problem since on the same routes.

This sensor is cheap, and easy to replace. Entire job took less than 5 minutes, and doesn't require a coolant drain. Something to consider if you find yourself trouble-shooting a heat problem.