I don't find UGGs too warm at all - I don't have this particular style, I have the classic short, but I have worn them constantly since I got them in November - that said...I don't actually wear them 'out' except to walk the dog or run very quick errands. I think they're quite ugly (at least the ones I have) and hate to see all the 'trendy' people wearing them with mini skirts and such...
I will wear my UGGs forever - they are the WARMEST shoes I've ever worn.