Both fans come on so I know they're working. It seems like when I'm idling at a long light or inside the automatic carwash that the temperature guage almost reaches the H indicator before the fans come on. While driving along and stopping at regular red lights, the temperature gauge stays below the middle. My question is what can this be? I tested this on my parking lot and let it sit in neutral and idle. The guage crept up 3/4 before the fans came on.

 

Sounds like an air pocket , Add coolant to the radiator when cool in the morning .If it's low periodically then you have a leak that lets air into the system . The air sits at the top of the engine and gets moved along when driving . Air may also sit in the water pump rendering it useless .