as long as its not too hot like 90 and above all dam day, lol , i always supply a basking area for my chams..its like the same thing for you to grab a jacket if you feel chilly( they always need a way to control body temps)..just imo...
Id say most chameleons that do bask would prefer and benefit from a basking spot year long regardless of the ambient air temps which can be controlled some way or another. Outside may be a different story the sun produces natural basking spot.Most houses are at least 65f in the winter time id imagine as well.
if you place it in the middle of the cage yes...but its a basking spot , so you place the light on one of the top corners of the cage , and with good amount of foilage with live plants, the temperature varies in the cage, plus misting also changes it...i use a infrared temp gun
Along with your chameleon needing a basking light to properly thermoregulate it also provides UVA that stimulates appetite. So in short, yes you need a basking site. You may want to lower the wattage of the bulb in the summer but IMO, and I only keep montanes which some say do not need them at all, you need a basking site year round.