Datguyyogi

Hey everyone new to the forum and just purchased a 1999 Honda Civic and it's overheating in traffic. I drive an hour to work in the morning and the car doesn't have any issues, but then in the afternoon when it's warmer the car overheats at red lights. I've replaced the thermostat and made sure there's enough coolant. There is no smoke coming from the exhaust and the oil doesn't appear milky, so I don't think its a cracked head gasket. But not sure what else to try or do, any recommendations would be greatly appreciated! Thanks

Wankenstein

Is the radiator fan coming on during the overheats or as it normally should?
Can test it by wiring 12v directly from battery.