When we were there in Dec. 2004 we had one day (I think it was Christmas day actually) that it just poured all day long. People still stood curbside 2 hours before parade time which made lines super short..that and all the people who left. Just remember to bring a few pairs of walking shoes so that the next day you have a dry pair. Ponchos seem work better than umbrellas, although they are not the most comfy of things to wear.