Heavy Weather (ヘビー・ウェザー Hebī Wezā) is an ability that unconsciously activates after Weather recovers his memories stolen by Pucci. Unlike the rest of Weather Report's abilities, Heavy Weather is automatic, stemming from Weather's rage against humanity.
Heavy Weather alters the refraction angle of the sun's rays entering earth's atmosphere with Weather Report's ability to control the weather. As a result, rainbows manifest in the surrounding vicinity. Those who touch the rainbows will perceive themselves as being a snail due to a natural subliminal effect created by the altered refraction angle. All animals are affected by the metamorphosis aside from Weather Report who is immune to the effect. Pucci theorizes that perhaps there is an image of snails being reflected within the sun's rays or the sun reminds organisms of their prehistoric instincts. The deep subliminal effect of the ability physically affects their bodies as well.
The transformation can be either a progressive change into a giant snail hybrid, a breakdown into numerous snails, or an explosion into a cluster of snail eggs that hatch immediately. One can also begin to turn into a snail by physically touching one of the snails created, or an individual already turning into a snail.
A partial transformation alone comes with a number of handicaps such as getting stuck on surfaces, sluggish reactions and speed, and loss of strength because of the softening of the body. Moreover, the victims also become vulnerable to snail-eating predators and contact with salt, which dehydrates the body.
Snails created through Heavy Weather can procreate freely thanks to their ability to change gender. The procreation is very fast and accelerates exponentially, causing a rapid multiplication of the snails. Any person trapped inside a swarmed area is practically doomed to be touched at least once and begin their metamorphosis. If left unchecked, the swarm of snails will endanger whole cities.
As discovered by Enrico Pucci, a blind person is immune to the effect of the Stand, since they can't see the subliminal messages carried through the sun rays. This allowed Pucci to protect himself by having Whitesnake extract his sight. Regardless, once a person starts transforming into a snail, unless Weather himself is killed, the process is irreversible.
- SO Chapter 129: Heavy Weather, Part 5
- SO Chapter 125: Heavy Weather, Part 1
- SO Chapter 134: Heavy Weather, Part 10
- SO Chapter 126: Heavy Weather, Part 2
- Volume 78, in-between Stand stats, SO Chapter 133: Heavy Weather, Part 9
- SO Chapter 130: Heavy Weather, Part 6
- SO Chapter 131: Heavy Weather, Part 7
- SO Chapter 132: Heavy Weather, Part 8