Starting from square 1...(Lincoln 7C Light Blue)

This is the first square of my "Temperature Afghan". I've assigned a colour to a block of 5 degrees centigrade, and the colour that I use will depend on the high temperature in the afternoon here in Lincoln. The projects that I've seen have done it in stripes or ripple stitches, but I fancied it in squares. In my notes that you can see, I've Googled the average low and high temperatures for each month, and the median. That way, I could get a vague idea of what colours I will mainly need to keep on hand.

I'm working in Rico Cotton Aran on a 5mm hook, and each square will be 4 inches, except for a centre square that will be 12 x 12 inches. It will be 22 rows of 17 squares, working to 68 x 88 inches, not including my joins or edge