When I lived in Thailand, I ate breakfast with a Thai family who sometimes would have steaming hot spicy noodles on a 90+ degree day. I thought it was crazy, but then I ate it and didn't feel any less comfortable (and it was delicious!!).
Though I still prefer cold cereal, there are specific cultural and physiological reasons behind the hot-food practice, as described in this Salon article.
EDIT: Article's main points:
Hot broth is thought to balance your body's ki, which is cool in summer, by fighting "fire with fire" and bringing it more in balance with the hot external environment. This might be similar to a Chinese concept where different foods have "hot" and "cold" designations and should be eaten in balance with each other.
The dish described, samgyetang, has garlic and ginseng. Garlic is an anticoagulant and ginseng causes blood vessels to dilate. The inc