Like maeve, my workload is heaview in winter. Water butts and drinkers have to be topped up by lugging bowsers and containers up the fields because everything's frozen, silage has to be provided because the grass isn't growing and animals tend to eat more in cold weather (particularly the sheep, because they're pregnant). Much of the work is slower because you're thickly dressed against the cold and moving around in darkness for much of the time. I wish could hibernate, but the stock wouldn't thank me for it.
In hilly areas it was common to have separate holdings for winter and summer - in Wales Hafod and Hendre - and stock would be moved downwards for the winter to be nearer the main homestead. That's still the case in alpine areas, where cattle and sheep are drafted down to winter pastures before the first serious snows. For the farmers, though, life goes on. And these days the long dark evenings provide plenty of opportunity to catch up on the inevitable paperwork!