One side of this reversible scarf shows a comparison of daytime highs and the other side, a comparison of night time lows for two widely spaced years. The 2 sides of the scarf are knitted separately and then joined with an Icord edging. All the ends are hidden on the inside of the scarf so there is no sewing at all, except to sew in the very last end. The wavy edge of the scarf adds interest and also marks each 2 week interval during the year. The center dividing stitch shows the changing seasons.

The data: In the US, all the daily temps back to the 1880s are available on this website https://www.ncdc.noaa.gov/cdo-web/search A Google search for ‘daily temperature records’ followed by your country name will likely find similar records for other countries. If you are handy with an Excel sheet it is very easy to download the data as a .csv file and put it into columns.
If not, you can simply print out the data as it comes from the website and use a highlighter pen to mark the columns you will be using in the scarf.

Sock weight yarn, 1 ball for each 10 degree F temperature change. If you are using a Celsius scale or are in a region where there are not great temperature differences, you may want to use a 5 degree change for each color.

The sample was knitted with 10 colors of Ice Yarns Baby Merino and 1 color of Lana Grossa Meilenweit 50g
If there is a particular temperature that occurs frequently, you may need two 50g balls of that color. Otherwise one 50g ball for each temperature is plenty.

An intermediate knitter should be fine with this pattern.