I recommend that you buy a timer for your chameleon enclosure. They are very cheap and extremely handy. A timer is a small device that can turn on or off the electricity at a certain time. You plug it into the wall and then plug a power strip into it. At this power strip you can connect the UV light, heat bulb and normal lights. It will automatically turn on the lights in the morning and off in the night, creating a very strong daily rhythm for your chameleon. Its internal clock will synchronize with the light and temperature, allowing it to have a circadian rhythm. This will make its body predict its environment better. Just before the lights switch off the chameleon will go to its sleeping spot to get ready for the night. This is much better than you doing the lights yourself, as that will never be as regular. And who has time for that anyway?
Setting the timer
You can set up the timer to be regular year-round or to follow the seasons a bit. Veiled chameleons are originally from Yemen, where there is a slight difference in length of day between summer and winter. In summer you can provide 14 hours of light and 10 hours of darkness, in winter you can reverse this with 10 hours of light and 14 hours or darkness. If you don’t want this hassle you can just stick to 12 hours light and 12 hours darkness year-round. The chameleon will pick up some of the natural light in your area anyway.
Some breeders will change the amount of light for their chameleons to regulate their mating and breeding behavior. The amount of light and especially the change in the amount of light per day will make females ready to mate or will postpone their egg production. If you are into breeding chameleons you should read more about the day/night rhythm and its influence on breeding behavior.
What does a chameleon do during the night?
A chameleon just sleeps at night. It is not active and will not eat or walk around. In the wild it is actually pretty easy to find sleeping chameleons. At night they turn light green in color. When you shine on the trees with a torch light, they really stand out.