Hector the thundercloud is very predictable. So much so, in fact, that it arrives on a daily basis with almost perfect timekeeping.
Telling the time using a thundercloud
Chris Littlechild - Grunge
Meet Hector, the massive thunderstorm that shows up every day - The Weather Network
Hector Thunderstorms
Chris Littlechild - Grunge
Astounding Stories of Super-Science, February, 1930, by Various.
Thundercloud Configurations Favorable For Radiation, 58% OFF
Weird Weather Phenomena - Smore Science Magazine
Grunge, History, Crime, Science, & Strange News
Meet Hector, the massive thunderstorm that shows up every day - The Weather Network
For the first time, scientists 'see' thunder
What are some great mysteries of the Earth that have been proven to have simple answers? - Quora