There's a possibility for that. I've also seen videos on YT, but they do not work for me. Is probably due to the version.
Try with / toggledownfall or / weather clear. If you have WorldGuard, you can easily disable the weather there in the config.yml.
Hay, just try with / weather clear. If no duration is specified with the / weather command, the set weather will last for five minutes. Otherwise simply disable it in the config
As a builder, I always build with gamerule configurations:
/ gamerule Doweathercycle false (weather stays the same all the time)
/ gamerule DodayNightcycle false (time stays the same)