Weather certainly can affect home sales but only temporarily. During a snowy winter you'll find fewer buyers looking at homes. And if spring arrives early, the buyers will be out just like the crocus. That's why real estate agents in CT hope that Phil does not see his shadow!
The weather can certainly affect property sales. A year and a half ago the central Nebraska area was hit by a terrible ice storm. Some rural residents were without power for up to three weeks. Not only were people not in the mood to be out shopping for a home in the bad weather, but lots of extra funds were spend on repairs from the storm and the need to buy expensive generators.