Wish mine ran cool a few minutes at a light and its hot....... that's when its 40 out...... good on cold days though.... like 10/20.......
(1) Does your fan kick on while your sitting there waiting on the light?
(2) Is your Anti Freeze mixture higher than 50/50 mix? A/F is thick and does cause poor circulation if the mix is wrong.
(3) Has the cooling system been vented at the highest point (T-Stat Housing) to rid it of trapped air? Trapped air will keep the T-Stat from working properly.
(4) Is your Rad or Oil Cooler obstructed with road debris or caked on bugs?
(5) Has the Cowling or Inner Cowling pieces around the engine been altered or removed? Proper cooling requires proper air flow.
(6) Check the coolant tank and it's hose and routing. If the engine can't retrieve coolant as it cools down it will become lower on coolant each time it heat cycles.
(7) As long your not puking coolant at the lights while waiting and not running in the HOT zone of the gauge you've little to worry over as these engines do cycle widely between cool and fairly warm on the gauge.