+1 for Yekaterinburg.
I'm ready to help with the organization; maybe I can contribute some extra money for the prizes, but I'm not ready to be the main organizer like I was in 2012. My brother might be able to help with welcoming guests or something else. Merlin might also be a good host with a show program, although I'm not sure if he's currently in Yekaterinburg.
The weather wasn't very favorable for us in 2012. In 2016, for example, it was +20...+25 degrees Celsius during the day and 0...+10 degrees Celsius at night, and it was sunny from the end of April.