Okay from now on, I will create a list of the weather effects from
Castform. But as I do not want to spoil anything, I will only add
the effects that have already happened.

Clear Sky - There is not even one cloud in
the sky. (All Normal Pokémon gain 50% more EXP.)

Rainy - Better take an umbrella. (All Water
Pokémon gain 50% more EXP.)

Cold - That's cold! (All Steel Pokémon gain 50%
more EXP.)

Hail - Watch out for hailstones! (All Ice
Pokémon gain 50% more EXP.)

Strong earthquakes - WARNING: There will
be powerful earthquakes from time to time. Better stay at home!
(All Ground Pokémon gain 50% more EXP.)

Very Sunny - Don't stay too long in the sun!
(All Fire Pokémon gain 50% more EXP.)

Gusty - That's gusty! I might get blown
away! (All Fighting Pokémon gain 50% more EXP.)

Mystic Aurora - ... What's that? That
aurora looks amazing! (All Psychic Pokémon gain 50% more EXP.)

Meteorites - Special warning: Watch out
for meteorites falling from the sky. (All dragon Pokémon gain 50%
more EXP.)

Small earthquakes - During the day it will
come to weak earthquakes. (All Rock Pokémon gain 50% more EXP.)

Thunderstorm - Wow, lightning! (All
Electric Pokémon gain 50% more EXP.)

Sunny - Oh, I like sun! Just like my
plants do. (All Grass Pokémon gain 50% more EXP.)

Windy - It blows a pleasant breeze. (All
Flying Pokémon gain 50% more EXP.)

Very foggy - I can no longer see my hands
in front of my face! (All Dark Pokémon gain 50% more EXP.)

Smog - A large cloud of smog moves from the big
city here. (All Poison Pokémon gain 50% more EXP.)

Muggy - Man, it's muggy today. (All Bug
Pokémon gain 50% more EXP.)

Foggy - The fog is blocking my view...
(All Ghost Pokémon gain 50% more EXP.)

Rainbow - Aww, there's a fancy rainbow in
the sky! (All Fairy Pokémon gain 50% more EXP.)
In case of emergency Plushie