With no explanation, label text_A→text_B with either "DON'T KNOW", "NO" or "YES".
text_A: Paris has a typical Western European oceanic climate (Köppen: "Cfb"), which is affected by the North Atlantic Current. The overall climate throughout the year is mild and moderately wet. Summer days are usually warm and pleasant with average temperatures between, and a fair amount of sunshine. Each year, however, there are a few days when the temperature rises above. Longer periods of more intense heat sometimes occur, such as the heat wave of 2003 when temperatures exceeded for weeks, reached on some days and rarely cooled down at night. Spring and autumn have, on average, mild days and fresh nights but are changing and unstable. Surprisingly warm or cool weather occurs frequently in both seasons. In winter, sunshine is scarce; days are cool, and nights are cold but generally above freezing with low temperatures around. Light night frosts are however quite common, but the temperature seldom dips below. While snowfall is an annual occurrence, it is uncommon for it to remain intact on the ground. The city sometimes sees light snow or flurries with or without accumulation.
text_B: Would it be very rare, almost unheard of, for Parisian children to wake up to a truly white Christmas, with snow on the ground as in story books?
YES.