Looked at the average highs for Vancouver BC for last year (2012) and saw that they ranged from 42 degrees F to 73 degrees F. So I kind of based my range for this year on that. I went 10 degrees lower as the first week or two of this year, the highs were lower.

I’m using 11 colors of Vanna’s yarn and going in increments of 5 degrees.

Here’s how it breaks down:
Above 74 degrees - Mustard (158)
70-74 - Rust (135)
65-69 - Brick (133)
60-64 - Cranberry (180)
55-59 - Olive (174)
50-54 - Fern (171)
45-49 - Purple (147)
40-44 - Navy (110)
35-39 - Colonial Blue
30-34 - Dusty Blue (108)
below 30 - Silver Heather (405)

base color - Patons Decor Cream
Not exactly ROYGBIV but it’s good enough!

Update: 4/9/13
I actually changed the colors around to be more like ROYBGIV when I got to 61 degrees. So now the top four colors are switched. Cranberry is now the hottest.

Update: December 2015 -didn’t like the look of the garter stitch so frogged the whole thing!

Still going to use the temps from 2013 since I have them.

CO 66 and joined in a tube. One rnd per day. Going much faster!

I ended up frogging this as the colors were not pleasing together. I have kept the calendar and will try it again with pastels. Also, I’m thinking of making an afghan instead.