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Bear Grylls explains that there are some “heavy hints” in nature for weather-related changes, mostly related to increasing or decreasing pressure, humidity in the air, or changing wind speeds. “It might seem a bit odd to take these old wives’ tales into account when there are such scientific forecasts out there,” says Bear. “But many of these old sayings have some basis in fact and they may be useful in the field where you have to make speedy decisions based on brief observations.”
Here are some examples of old wives’ tales, and what they’re telling you:
Anecdote: Red sky night, sailors’ delight; red sky morning, sailors take warning
Truth: High pressure systems—which often bring warm, dry air—sometimes suspend dust particles in the atmosphere. Weather systems generally approach from the west, so if the sun sets through dusty air (giving the sky a reddish appearance), it may mean a high pressure system is approaching. A reddish-hued sky in the morning may indicate that a high pressure system has passed and may have left a low—pressure system in it’s wake. Low pressure systems often bring moisture and foul weather, hence, the sailor’s warning.
Anecdote: There’s a calm before the storm
Truth: Some storm systems draw warm, moist air into the clouds, which leaves a low-pressure vacuum behind. The vacuum pulls warm dry air that’s passed through the clouds back toward the ground. Warm, dry air is relatively stable, so it can feel calm. Sometimes animal behavior also changes, with critters looking for shelter or stockpiling food, contributing to a sense of calm.
Anecdote: When a halo rings the moon or sun, rain’s approaching on the run.
Truth: A ring around the moon or sun is a result of light refracting through ice crystals or water droplets in the upper atmosphere—where thin, cirrus and cirrostratus clouds exist. Both cloud types often precede rain, though cirrus clouds are also associated with several days of fair weather first.