While asking another question about Jormungandr, the Snakebot of Doom, a point was made that it is so big and hot that it might produce its own weather effects. To that end:
Jormungandr is 446 metres in diameter, weighs 1.486 billion metric tons, has a body that is cylindrical for 7480m, and then tapers down to a point over a further 669m, the tail matching with a similarly shaped mouth. Its armour is made from Tungsten-depleted Uranium alloy plates with a smooth surface coating of Boron Carbide, at the surface appearing to be overlapping scales around five metres long and half a metre thick, much like the scales of a snake. Most importantly to this question, it is driven by shape-memory-alloy 'muscles' that have an operational temperature of around 97°C/207°F, and it has a similar surface temperature in air due to its cooling requirements, but the skin temperature would be much lower in water.
In order to power its huge demand for energy, it is equipped with six hot-fusion reactors, each of which is capable of producing enough energy to power its shape-memory-alloy muscles or its entire complement of rail guns.
While it is rolling sideways, when steamrolling a city, it moves at around 5kph / 3mph. However, it is capable of slithering in a serpentine manner at up to 20kph, and can roll into a hoop and travel at around 100kph on a level surface. It is also capable of travelling underwater, at up to 30kph rolling or 15kph slithering.
In its travels from its construction site beneath the highest point of the Antarctic ice cap to the sea, it rolled at high speed, then travelled along the mid-Atlantic ridge (an area with high levels of geologic and thermal activity), and then surfaced off New York City, which it is presently flattening.
In each of its movement regimes, both above and below water, what effect might Jormungandr have on local and global weather patterns?