Unlike dogs which cycle about every 6 months, there is no schedule for a cat. They can cycle every 2 or 3 weeks endlessly. Heat cycles are different for every female both in frequency and length of time they last. On AVERAGE, a queen will go into season for a period lasting about 10-14 days, stop for about 2-3 weeks and then start up again. In the winter when days are shorter, they tend to stop cycling for about 2 to 3 months during the shortest days.
Females may also spray and will often urinate inappropriately when they are in season so spaying is the best 'fix' for the problem in the majority of cases.
Please let me know if I can assist further.