Even with the cold weather in New York this week, there isn't any concern in WWE about bad weather for WrestleMania 29. If you look at historical weather data for April 7 in the area, the average high is 59 degrees and the average low is 37 degrees. The record high is 78 degrees and the record low is 17 degrees.
The Old Farmer's Almanac predicts "sunny" and "pleasant" weather for the week. Take that for what it's worth.