There are clearly seasonal effects: taking reported UK residential property completions over £40,000, the government statisticians seasonally adjust the numbers, for example increasing the January figures by about 32% and reducing the June numbers by about 12% each year, to smooth out the repetitive patterns and make other factors such as the impact of the recent recession more obvious.
So people buy houses more often in summer than than in winter and my guess is that at least some of that is weather affected.