BE YOUR OWN WEATHER FORECASTER

"You don't need a weatherman to know which way the wind blows".
Bob Dylan

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
Look for steady rain or snow when:
  • 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
Look for more bright weather when:
  • 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
Look for clearing skies when:
  • 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)
Look for heavy snow when:
  • 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
Look for temperatures to rise when:
  • 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
Look for temperatures to fall when:
  • 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
Look for fog when:
  • 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
Compiled by:

David Phillips
Senior Climatologist
Environment Canada
August, 1997
 
Homepage

URL: http://www.cmosarchives.ca/beyourforecaster.html