I live in Wrocław, not Kraków, so I can't tell you anything about the city specifics.
About the winter - recently winters in Poland are mostly snow-less and the temperature usually doesn't fall very low as well. There's a lot of rain, water, puddles and mud though. I think cycling should be kinda possible for most of the winter but I wouldn't expect it to be very pleasant. I, for one, use my bike as much possible in summer but definitely prefer public transportation during winter.
Since you're so concerned with Jerboa quality I'm pretty sure the developer would appreciate if you volunteered for performing comprehensive quality control before each release.
I live in Wrocław, not Kraków, so I can't tell you anything about the city specifics.
About the winter - recently winters in Poland are mostly snow-less and the temperature usually doesn't fall very low as well. There's a lot of rain, water, puddles and mud though. I think cycling should be kinda possible for most of the winter but I wouldn't expect it to be very pleasant. I, for one, use my bike as much possible in summer but definitely prefer public transportation during winter.