Any whether change can affect the tuning of any nitro engine. Unless the temperature, humidity and so on stay the same some retuning is necessary for a peak tune. Say you start running early in the morning and by the after noon the temperature changes 10 degrees this could affect your tuning. I just do not see spending $20 to $30 on a gallon of fuel and not willing to spend that on a temp gun that helps keep your expensive engine safe.