I also am taking ortho tri-cyclen lo and I looked on the packaging and it says to store it at 59-86f degrees . I'm not exactly sure whether or not going above or below this would hinder the effectiveness of the pill, but I mean they did put it on the packaging so it would be best to keep the pills within that range temp wise. I would just say its better to carry around in your purse just because the inside of a car can get pretty hot. I hope this helps!

Thanks! I never noticed that on my packaging... It did help!