Lea from Leafcutter Designs prepared balls of wool which matched the different colours of the sky. She had 6 different shades as you can see in the photo below. Each day she would look outside to see what colour the sky was that day. She would then do just two row of knitting each day, matching the colour of the sky with the ball of wool she chose.
Each day has 2 rows of garter stitch completed.
Here is the pattern if you want to do this yourself!
Check out her video here where she explains things more fully and shows how she manages all her balls of wool. Instead of one ball of wool, she has done 2 smaller balls so she can do a mix, for example on a blue sky day with some white clouds, she knits the blue and white yarns together that day.
I love this. She calls it 'conceptual knitting'. At the end of the year, it is a 5 foot long scarf!