They can call every three weeks or even more often if they are not bred. Or they can go for ages - one of mine called at five months and then didn't call again until she was 13 months. Then, just to complicate matters, most don't call in the autumn (in my experience) - at least, if they are allowed out they don't. Indoor cats seem to call all year round if they live in centrally heated houses.

Assuming you didn't let her out in January when she called, she could call again at any time.

Liz