Yeah, it's a tricky one, which is why I think the others should perhaps be reversed. Just make the symbol mean 'I feel **** - deal with it'. So the snowflakes is 'I'm too cold', the sun in 'I'm too hot'.

I gues that 'dry weather' is often symbolised as 'parched, cracked earth', but that really doesn't work when shrunk down to icon size.

My worst experience with aircon symbology was my first chilly winter morning in Japan - all the buttons were marked with kanji characters. I prodded away, shivering in my pyjamas, but beacuse aircon takes a while to kick in, and the 'heating' function will begin by pumping out cold air until the heat pump starts up, it takes a loooong time before you can work out what each one does.