Every year, weeks before the actual show, I begin making a checklist of things I need to bring. Don't do what I did one year and leave something major behind - trying to find someone who had an extra full noseband was harder than I thought. Thankfully everyone was really helpful and generous and I was able to borrow one in the end. #fatheadproblems
I've attached a link to my checklist below. This is the one I use so may need to be altered a bit for anyone else. I camp every year I go and as a rule of thumb you either get burnt or drowned at the festival - there is no in-between! So definitely pack for both types of weather, no matter what the forecast says!
Link: AIRC Festival Checklist
If I have forgotten anything please let me know!