There are many blue bricks and gray tiles in the quadrangle, and the color is not bright. What does it have to do with the local climate?

This has nothing to do with the climate. Because the bricks burned in brick kilns are red when they are not watered, yellow when they are half cooked, and black when they are watered. Glazed tiles are painted with colored glaze and yellow glaze before entering the kiln. When fired, they are yellow tiles, and when painted with green glaze, they are blue tiles. Glazed tiles are too expensive for big landlords to build, so they have to use ordinary tiles. The poor can only build huts with earth walls.