I've seen similar ideas with temperature blankets, choosing different color gradients for different temperature ranges. A lotta folks don't make a full square for every day, but usually do a row for every day. Some do a row of daily high, and a row of daily low. But even so, 365 rows makes for a long ass blanket.
I'm jealous of your granny squares
@Dirona. Mine still don't look good enough to actually assemble into anything.