Ladies and Gentlemen, this is the most awesome project idea I have seen in a while!
I was just looking at Pinterest and saw a pin and, long story short, found out about "Weatherghans" and "Temperature Blankets".
I saw that people are also making scarves with this idea. The concept is simple. First you assign colors to a range of temperatures. You can use the chart on the site I link to below, or even pick your own colors. Buy the yarn. You find out the high temperature of the day, for every day of the year, and knit or crochet a row in that color for that temperature. You can do this on a daily basis, starting in the year you are in. Make a row every day, and by the end of the year you have an afghan!
This site, The Crochet Crowd, is awesome. There is a download for the temperature chart, a pattern for a thermometer that you can make and appliqué to your piece, and even a chart that will tell you what hook (for crochet) to use and how many stitches to use for the size blanket you want to make. And there's a link. The link is to a site that is incredible. You put in the zip code for the area you live in and the year that you want to do (in the past), and it will give you the chart for the afghan. You can see that chart in the picture below.
Check out that web site and try one for yourself! It's a great idea!!