The outside temps shouldn't affect your BP IF the temps in the tub are kept constant. However, sometimes they will fluctuate as the house temps fluctuate. And that can throw them off feed. Also, there's nothing we can do about the barametric pressure that comes with weather changes. It seems that snakes are sensitive to that, so even if you are able to maintain perfect temps and humidity year 'round...they may still feel the difference in weather and trigger a season of light eating.
If the snake begins to consistently refuse (and all other reasons for refusal have been ruled out)....you can drop your offerings down to every two weeks and maybe try slightly smaller prey size than usually offered. Be glad when the snake eats....don't worry too much if it doesn't.