Cycling starts in most female animals after winter solstice when the days get appreciably longer. Estrus is triggered by daylight hours and can be brought on deliberately by indoor living (small animals) or lights on timers (large animals). Light also triggers shedding.
From January to June and then July to December - all over the world. You can find kittens born in every month of the year. Most litters are born mid sping to early fall no matter where you live.
It mostly depends on the climate- in colder places it'll start in spring and go to late fall, though it could be anytime. Most cats have a litter in spring and one in fall, though many factors depend.
In warmer places it's any time. Really, whenever they're in heat