The general idea behind this is widespread in many areas, certainly Europe also.
Fine spells in winter tend to to preceed a further period of snow or stormy weather?
Well maybe, but the real point is that it can start to feel like winter is nearly done if the sun is out, as it now has a little power again.
But the worst part of winter is often towards the end, as the cold to the north is now at it's height - and interacting with the first plumes of warmer air from the south can cause *trouble* !