If my calculations are correct, the brown rabbit's fur turns white so they can camouflage in the snow and their body temperature heats up during the winter, so if the temperature during the winter is below i believe you will see more of white rabbits which means there is gonna be a lot of baby rabbits too because they'll be mating a lot too.
The Brown rabbits come out a lot during the spring/summer/fall time when the weather is warm, but I believe if the weather is too warm they will go into hiding find a place that can cool them down so the population for them is quite different then the white rabbit. So that is what i think.
Hope this helped :) Have a great day