By noting cloud formations, wind direction, sky colour, and temperature and moisture changes, you can often predict accurately sunshine and rain, calms and storms. Here's a handy list of practical weather signs that can provide a hint as to the weather ahead. A Greek weather sage once said, when two weather signs agree, forecast with hope, when three confirm one another, forecast with confidence.

Look for cloudy, unsettled weather when:

• the barometer falls steadily
• the wind blows strongly in the early morning
• the temperature at night is higher than usual owing to clouds
• the temperature is far above or below normal for the time of year
• clouds rapidly move in various directions at different levels
• high, thin, wispy clouds (cirrus) increase in amount, thicken and lower, sometimes producing a ring or halo around the sun or moon
• clouds darken on a summer afternoon
• high- and/or middle-level clouds darken and move from the south and southwest
• the sunrise is red

• the barometer falls steadily (if the pressure falls slowly, rain or snow will come within a day; if it falls rapidly, expect precipitation any minute)
• winds blow from the southeast to northeast and north
• clouds are low and uniformly flat and grey
• leaves show their undersides as strong south wind in advance of the rain will flip the leaves over
• there is a ring around the sun or moon

• the barometer is steady or rising slowly
• a gentle breeze blows steadily from the west to north
• winds swing from south to southwest or from east or northeast to the northwest
• cloud (amount and number) decreases in the late afternoon
• cloud base rises and humidity decreases
• evening sky is clear and you can look directly at the setting sun which looks like a ball of fire
• morning fog breaks within two hours of sunrise
• the night before heavy dew or frost occurs
• the moon shines brightly and the wind is light
• a bright blue sky with high thin wisps of cloud

• the barometer rises
• the wind shifts to any westerly direction (especially from east through south to the west)
• the temperature falls rapidly, especially in the afternoon
• increasing breaks in the overcast
• clouds become lumpy
• dark clouds become lighter and steadily rise in altitude
• fog lifts before noon
• frost or dew is on the grass
• Look for showers (thundershowers) when:
• the barometer falls
• winds blow from the south or southeast
• the morning temperature is unusually high, air is moist and sticky, and you see cumulus clouds building (rain within six hours)
• dark, threatening thunderclouds develop in a westerly wind
• thick, fluffy (cumulus) clouds develop rapidly upwards during early afternoon
• you hear loud static on your AM radio (thunderstorms within the hour)

• the barometer falls rapidly
• winds blow from the east or northeast
• the air temperature is between -10 oC and -1oC
• a storm lies to the south and east of you

• the wind shifts from the north or west to the south
• the nighttime sky is overcast with a moderate southerly wind
• the sky is clear all day

• the barometer rises steadily (in winter)
• the wind shifts into the north or northwest from the south
• the wind is light and the sky is clear at night
• skies are clearing, especially in the winter
• snowflurries occur with a west or north wind

• warm winds are blowing humid air across a much colder surface (either land or sea)
• the sky is clear, the winds are light, and the air is humid the night before
• warm rain is falling ahead of the warm air
• water temperatures are warm and the air is much colder

David Phillips
Senior Climatologist
Environment Canada
August, 1997
 

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