I'm in michigan and it is the dead of winter. I can vouch for what cainschams is saying. The sun goes down around sixish here and my chams are all curled up by then so I just have the timers go off then and come back on when It get light. Even if I leave the lights on longer or turn them on earlier they don't leave their sleep spots til the actual sun come up. Also there is a derease in appetite in about half of my chams. Mostly the males for some reason that I am oblivious to, the female eat like hogs all rear round generally though. So if the sun is going down and he is getting ready for bed about 30-60mins before that I wouldn't worry. As long as he is still eating on a regular basis, even if its only 3-6 cricket every other day I wouldn't be worried. I have a Adult male ambilobe panther that literally eats one or maybe two days a week in the winter. However on that one day, which is always friday or sunday for some odd reason, he will eat 3 or 4 adult dubia, 4 silkies a super or two and a big hornworm. idk why but he is a binge eater in the cooler months. the vet has done every test imaginable and he is completely healthy. Good luck and if he stops eating and rink for over 7 days, although they can go alot longer without eating, then I would worry.