Things associated with winter with U

• Umbrella

  Used in winter for rain or snow protection.

• Under the weather

  Idiom often used for winter colds and flu.

• ugly sweater

  Classic Christmas party wear in cold winter.

• Undercoat

  Extra coat layer for warmth in cold winters.

• Under the tree
• Under the snow
• Under the covers

  Cozy spot hiding from cold winter nights.

• Under the mistletoe

  Romantic Christmas/winter tradition for kisses.

• Underwear thermal

  Warm base layer, often worn in cold winter.

• Under the Christmas tree

  Classic Christmas image, very winter‑y.

• under the blanket

  Cozy winter activity to stay warm.

• ugly jumpers

  Ugly jumpers = famously worn at Christmas time

The words in the list Things associated with winter with U come from players of the word game City, Country, River.