Yellow streaks are visible in the sky at sunset. Smoke descends instead of rising. Fog comes from landward direction. Fog settles down toward the ground. The sun looks blurry or hazy, or has a halo.
Stars twinkle more than usual.
Flowers are especially fragrant. Trees show the undersides of their leaves. Birds fly low, or do not fly at all. Birds are noisier than usual. Cows huddle in the field and turn their tails toward the coming storm.