The New Hampshire timeline in Breaking Bad doesn't make much sense only with respect to the snow. If Walt leaves in March, the weather in northern New Hampshire probably still has snow on the ground through the month. We see Walt grow a full head of hair over the time that he is in NH, and we see the vacuum cleaner man come up at least one other time and he comes once a month.

We also know that Jesse was stuck with the nazis for a while cooking meth. Finally, we know that Walt is at the dinner on his way in with the M60 on his birthday, which google tells me is Sept 7.
We also know that Skyler has been interrogated by the police, moved out of the house, and found a new job.
So Walt had to be in NH for about 5 months, from March 2010 until August 2010, and that he drove down from NH at the end of August/beginning of September, and arrived near ABQ on Sept 7.
Bottom line, they shouldn't have had Walt in a snowy car after he called himself in. It made for a nice bit with him hiding and all, though.