We cooled down by swimming in the river.

我们在河里游泳，好凉凉。

Thank heavens, it's cooled off a little.

谢天谢地, 天气总算凉。

After canicule, autumn will soon come, and it'll be much cooler.

过三伏，秋天就，就凉很多。

It will be cooler when the sun has set.

太落山之后会凉。

We could get some coolness here.

儿凉。

Keep in the shade; it's cooler.

你就在阴凉处呆着吧, 那儿比较凉。