Riding in winter

Astronomically, it starts with the winter solstice (around December 21 in the Northern Hemisphere and June 21 in the Southern Hemisphere), and ends with the spring equinox (around March 21 in the Northern Hemisphere and September 21 in the Southern Hemisphere). In meteorology, it is by convention counted instead as the whole months of June, July and August in the Southern Hemisphere and December, January and February in the Northern Hemisphere.

However, in the United Kingdom and Ireland the winter solstice is traditionally considered as midwinter, the winter season beginning November 1 on All Hallows or Samhain. Winter ends and spring begins on Imbolc or Candlemas, which is February 1 or 2. This system of seasons is based on the length of days exclusively. The three-month period of the shortest days and weakest solar radiation occurs during November, December and January in the Northern Hemisphere (May-July in the Southern).

That's from Wikipedia/Yahoo answers and it's rubbish - November 1 as the start of winter?! Winter begins technically 21 December, but is generally considered as 1 December onwards. They just said this on Radio 4 so it must be true.