It doesn't really get warm enough in England for it to affect me. But I took your advice CanisLucidus and I decided to get back into the habit of reading a book before I go to bed to take my mind off the day. I used to read every night before bed ever since I was about 12. For some reason I stopped about a year ago. After about 30-40 minutes of reading at night I normally feel really tired and I can get to sleep pretty easily after that.