Oil Temp reading?!
 

My car a 65 356 sc runs well, however the temp needle after about 20 mins of driving slips by the half way point. This happens during the day. At night in never goes by the middle mark. This troubled me so after logical deduction I turned on the hheadlights on during the day and the needle stays put at the haf way mark. What should I believe and what connection if any could exist between the headlights and my oil temp?

Thanks