Having just experienced first hand the combination of deep-frozen, dark-dayed December and ferociously beautiful, beautifully ferocious newborn baby, I can see precisely why a Middle Eastern birth of unknown date got locked into to the timing of the north European midwinter. Boy, does that myth work.
It came in like a wave, an oceanic coldness that spread across the landscape and pinned down every living thing. It was joyous, some days manifesting from invisible, spiky air as a fresh snow-dust, others sending everything from puddles to lakes to taps into deep freeze; on one morning a hoar-frost millimetres deep made the world a landscape of spiny glory; the next it had gone, and a sequence of snap-thaw snap-rain snap-refreeze had turned every surface into a transparent ice rink.
And then, with the shocking unpredictability of all tides, it had gone. I mean, we know when high tide will be as surely as we know when it is midwinter: but the actions of a given wave are subject to a billion factors of chance, are of incalculably unpredictability, and thus it is with real weather. And Christmas in the countryside was not-quite-white, if still with very real stretches of unthawed patina on the landscape.