I decided I will do two half square triangle blocks per day. Each one will have a black triangle and the other triangle will represent the temps for the day. I'm planning on a high column and a low column for each month, so my quilt will be 24 columns across and 31 rows with 2.25" finished squares, so it should finish up at around 54" x 69" or so. Months with less than 31 days will be extended with HSTs that use white in place of a color.
Will be shopping my stash of very pale batiks for the colored portions of the squares.
Rob