haul, noun = sun (the aul sounds like aisle)

Related words:
heulog = sunny
heulo = to be sunny
heulwen = sunshine
torheulo = to sunbathe
lliw haul = suntan
llosg haul = sunburn
sbectol haul = sunglasses
codiad yr haul = sunrise
machlud = sunset

Examples of usage:
Dw i’n hoffi codi’n gynnar er mwyn gweld yr haul yn codi = I like to get up early to see the sun rising

Mae’r haul yn machlud = the sun is setting

Yn llygad yr haul = in the sunshine (lit. “in the eye of the sun”)

Mae hi’n heulog iawn ac eitha boeth ym Mrighton heddiw = It’s very sunny and quite hot in Brighton today.

Dw i’n mynd allan i mwynhau’r heulwen rŵan. Time to go out any enjoy the sunshine now!