Temp Gauge Probs

In my teg the temp will periodically go to hot but the engine isnt actually overheating or acting funny nothing. The only thing i have noticed is when it does that my heat blows cold air. Not sure if both my cooling fans are fully operational. BTW the temps here i chicago lately have been in the 40’s and 50’s so thats why i dont understand. Gauge,Thermostat,Sensor? Anyone who has any explanations or ideas let me know:sad: