Lord Mayor's parade in London

I was lucky to witness the Lord Mayors parade in London last Nov . 08, 2008. I was there! This parade only happens when there is a newly elected Mayor in London. Sorry guys, for now I don't know exactly how often they have this. any idea out there?? My friend in London told me that, As long as there is a newly elected mayor, then this parade is taking place. It was raining very strong as we watched this parade. See the street, it is very wet...I guess this is the weather in London all the time. you can be very lucky if it is sunny when you go there!! happy trip in advance!!