Yes, ALMANACS is a Scrabble word!

Letter values in Scrabble US: A 1, L 1, M 3, A 1, N 1, A 1, C 3, S 1.

Is it a valid word?

ALMANACS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

an annual publication including weather forecasts and other miscellaneous information arranged according to the calendar of a given year
an annual publication containing tabular information in a particular field or fields arranged according to the calendar of a given year

Also: farmer's calendar.