Average hours per day (American Time Use Survey) This term refers to the average number of hours spent in a 24-hour day (between 4 a.m. on the diary day and 4 a.m. on the interview day) doing a specified activity.
Usually a cats first season is somewhere between 4 and 10 months old with average age around six months. Siamese and Burmese cats are quite precocious and will often have their first season at 4 months of age.
This means that while feral cats have a breeding season, with kittens born in the spring and early autumn, your house cat can go into heat at any time, and will probably do so every three to four weeks.