The Germany time line is quite correct for the northern hemisphere. My Singers begin heat cycles in August and the second a few months later, and sometimes a third end in mid winter. I have a male pup from a third heat cycle that was born in early spring like a wolf or coyote. This breeding only occurred because I had them separated for the first 2 cycles, thinking them over, then put them back together. Then the third happened, with pregnancy as the result. 3 Heat periods in 6 months or less is quite remarkable for any canine.