Mist rising from the pond, fair weather tomorrow. Clear moon, frost soon. When mountain moss is soft and limpid, expect rain. When corn fodder stands all dry and crisp, go on your outing, there's no great risk. Doors and drawers stick before a rain.
Knots get tighter before a rain.
Ropes shorten before a rain. When locks turn damp in the scalp house, it will surely rain. Guitar strings shorten before a rain. Dandelion blossoms close before a rain. When the milkweed closes its pod, expect rain.