This is my Granny Square weather blanket from Nov 2022 - Oct 2023. I made it in a DK wool with a 4mm hook, all triple crochet, one round per day, so each square is a week. It's ended up about 1.2m x 1m with the border included. I knew there weren't enough weeks in the year to make a pleasing rectangle, so I added the weather we had on a two-week holiday as well.
I'm in South Wales, where the temperature range is not massive - we rarely have daily temperatures below 2C or 3C, and not very often over 25C. Instead, I decided to record by atmospheric conditions (i.e blue sky, sunny intervals, rain etc.) for temperatures of less than 6C, between 6C and 16C and over 16C. I ended up using 18 colours, most of them I didn't use more than 25g of wool and the one I used most still wasn't more than 100g.
You can check for previous weather online with Accuweather, but I mainly used the Met Office to check the temperature and the rest of it was just gazing out of the window.
I loved making it, and am pleased I chose the colours I did.