Talk:Shadow Play - Part 2/@comment-1031724-20180515201251/@comment-7345250-20180911193820

Possibly. In the real world, the longest day of the year is the summer solstice, which traditionally falls on June 21st. There is nothing to prove it, but it is possible that ponies did not begin celebrating the victory until the height of summer.

More likely is that the celebration was on hold until Celestia recovered from her fatal battle, both physically and emotionally. That could have been anywhere in the range from days to months, but it probably was not instantaneous. There is also the matter of spreading the news and organizing the festivities, of which we know little.