When the milkweed closes its pod, expect rain. The ppitcher plant opens wider before a rain. Chickweeds close their leaves before a rain. Closed is the pinkeyed pimpernel before rain. If smoke falls to the ground, it is likely to rain.
Campfires are more smky before a rain.
The factory smoke stack is more of a nuisance before a rain. If toads apear in large numbers, expect rain. If frogs make a noise at the time of cold rain, warm dry weather will follow. If many earthworms appear, rain will follow. If you see toadstools in the morning, expect rain by evening.