What's a good hair length for the cold months? I'm not sure quite how long it's been since Hermione had a full body groom and I think it's time to shave her again. My mother thinks I should let it grow some more for the winter months though. I also want to shave her to cut down on the constant matting from her coat change but I only have a number 5 and a number 10 blade. I usually do a kennel cut with the 5. Right now the weather has been hanging around 50 F but it will get lower I'm sure. So what is a good length, and a good blade number?