Technical problem with my home alarm system: is there a way for me to fix this?

My alarm had been going off mysteriously & it took me forever to figure out that the front door was the culprit. It would seem that when the weather heats up in the afternoon (the door is facing west), that for some reason the trip on that door becomes overly sensitive. I can tell because barely jiggling the door makes the alarm go off. I can only think it's either the bright sun light or heat causing it, but why and how to fix?