When the air is hot and humid, there is a feeling of dullness and stagnation. Everyone is oppressed by lassitude. As the seasons begin changing, fresh air comes from the arctic. Clouds that have been building up begin to dispense rain, and damp air is exchanged for fresh, cool breezes. At night, the heavens are changing so quickly that lightning flashes from colliding clouds, and thunder heralds the revolving of the skies.
~ Deng Ming-Dao