In the quiet embrace of the changing season, Teiga pened this delicate yet profound haiku.
over the tatami mats blows
the autumn wind
—Teiga

We are talking about a simple house here, a “grass hut” symbolizing simplicity and impermanence. This kind of hut wouldn’t have kept out the weather very well, especially allowing the wind to blow straight in, which could be good or bad but certainly would bring us closer to nature.
The idea of allowing the wind straight in may sound somewhat miserable, but the autumn wind is not thought of as being especially cold; it is more a gentle reminded of the season, bringing to us that crisp autumn smell that is a pleasant welcome after the hot and humid summer. When that scent hits us, it brings a tranquility, where the hustle of the world fades away, and one is left with the simple, yet profound beauty of nature. I think that’s why most of us enjoy autumn.
From Wikipedia
Tatami mats were the traditional floor coverings of Japan. They are typically used in karate practice halls or other Japanese martial arts, so you may be somewhat familiar with them. They are made from straw and are soft to walk on. They are beautiful, give off a pleasant fragrance, and are nice to sit, walk, and sleep on. Unfortunately they are rather expensive and somewhat difficult to maintain, so newer houses no longer have them, or at most limit them to a single room.
The kigo (season word) in this haiku is autumn wind. It is a kigo for all of autumn. The nature of this wind changes as the season progresses: it starts with the residual heat of summer and gradually becomes cooler and more refreshing, and by late autumn, it carries a chill, contributing to a more desolate atmosphere.