Higher than ususal Engine Temps
 

Not sure I have a problem, but my engine coolant have been running about 10* - 15* F higher than usual, over the last 6 months (May - October). The car DOES NOT OVERHEAT and has maintained normal coolant levels. The car normally runs 186 -192*F, but I am now seeing 200*F for the past months during normal driving. The maximum temp I have seen in logs while driving is 212* I have made no changes the car over at all except I switched my brand of oil from Castrol to Total Lubricants, and it has been running in it current form for about 4 years. My car is single turbo 500+RWHP occasionally driven on weekends and has all the necessary cooling mods such as KOYO Rad and heat shields. I have checked the usual culprits such as operation of the fans, water pump fins, replaced thermostat, replaced coolant thermo-sensor.

Could it be related to higher ambient temps (GLOBAL WARMING)? Logs for last year summer were checked and the normal operating temps never got quite this high.

Any Ideas guys on what could be causing higher coolant Temps?