Different types of clouds?

[Klave]

One day when I was playing New Leaf, I noticed the clouds looked super different. I know there are cloudy days or thunderclouds but these looked really different so I took a screenshot. They looked like this:

And here is a different day where the clouds look normal - the clouds I normally see in the sky.

The different clouds lasted for a whole day if I remember correctly. Was something going on and did I miss it? Has anyone else seen these other clouds?

 

[Celty]

Clouds change based on weather and climate. It's not uncommon to see different types of clouds when you're playing.

http://animalcrossing.wikia.com/wiki/Weather

 

[Klave]

Ah yeah, I see now:
"In Animal Crossing: New Leaf, some towering vertical clouds known as cumulonimbus clouds can appear in the sky between the hours of 9am and 3pm in the month of August. They can also appear at any time of year during the Island Tours. They will appear very large and look like cloud-like mountains in the background."

Huh, that was the first time I ever noticed them!

 

[HungryForCereal]

the first picture is broken