I watch temperatures worldwide, and I have observed that 100-degree readings occur much more frequently in the Northern Hemisphere than in the Southern. Why?
Your observation is correct, although some locations in the Southern Hemisphere (in Australia, for example) routinely log temperatures of 100 degrees or higher in the summer. However, very high temperatures occur much more frequently and at many more locations in the Northern Hemisphere than in the Southern. The ratio of land to oceans is the explanation. Oceans moderate air temperatures, greatly reducing the occurrences of very hot and very cold temperatures. Intense heat is mainly a characteristic of continental interiors, and most of the Earth’s large land masses, and consequently its heat, lie in the Northern Hemisphere.