Yup, you know what, i too fall into this category. I have some problem with high temperatures. I live in Noida alone. As i am workin as a trainee software developer, i can't afford ACs and all, at this time. And these days, the environmental temperature during day makes me dull and sleepy. I donno what is wrong with me, but this happens with me and if sun is shining right over my head, my "processor" gets really hot
Also there are other things to bother you in daytime, work, girlfriend, phones, sounds of things, other people etc. At night, its completely silent everywhere which results in better concentration.