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wind barometer table to predict weather forecasts | The Old Farmer's Almanac

Predicting Weather Using a Barometer and Wind Direction

Wind/Barometer Table

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Use a barometer to forecast wind direction and the character of upcoming weather.

Here are some general statements of wind-barometer indications that are generally applicable to all parts of the country:

  • When the wind sets in from points between south and southeast and the barometer falls steadily, a storm is approaching from the west or northwest, and its center will pass near or north of the observer within 12 to 24 hours, with wind shifting to the northwest by way of south and southwest.
  • When the wind sets in from points between east and northeast and the barometer falls steadily, a storm is approaching from the south or southwest, and its center will pass near or to the south of the observer within 12 to 24 hours, with winds shifting to northwest by way of north. The rapidity of the storm’s approach and its intensity will be indicated by the rate and amount of the fall in the barometer.
  • As a rule, winds from the east quadrants and falling barometric pressure indicate foul weather, and winds shifting to the west quadrants indicate clearing and fair weather, but again there are exceptions and in some parts of the country these rules do not apply.

The following table generally summarizes wind and barometer indications in the United States. The amateur forecaster should modify the table in accordance with his or her own observations.

Wind/Barometer Table

Barometer
(Reduced to Sea Level)
Wind DirectionCharacter of Weather Indicated
30.00 to 30.20, and steadywesterlyFair, with slight changes in temperature, for one to two days
30.00 to 30.20, and rising rapidlywesterlyFair, followed within two days by warmer and rain
30.00 to 30.20, and falling rapidlysouth to eastWarmer, and rain within 24 hours.
30.20 or above, and falling rapidlysouth to eastWarmer, and rain within 36 hours.
30.20 or above, and falling rapidlywest to northCold and clear, quickly followed by warmer and rain.
30.20 or above, and steadyvariableNo early change.
30.00 or below, and falling slowlysouth to eastRain within 18 hours that will continue a day or two.
30.00 or below, and falling rapidlysoutheast to northeastRain, with high wind, followed within two days by clearing, colder.
30.00 or below, and risingsouth to westClearing and colder within 12 hours.
29.80 or below, and falling rapidlysouth to eastSevere storm of wind and rain imminent. In winter, snow or cold wave within 24 hours.
29.80 or below, and falling rapidlyeast to northSevere northeast gales and heavy rain or snow, followed in winter by cold wave.
29.80 or below, and rising rapidlygoing to westClearing and colder.
Note: A barometer should be adjusted to show equivalent sea-level pressure for the altitude at which it is to be used. A change of 100 feet in elevation will cause a decrease of 1 ⁄10 inch in the reading.
About The Author

Heidi Stonehill

Heidi Stonehill is a senior editor for The Old Farmer’s Almanac, where she focuses much of her time on managing content development for the Almanac’s line of calendars. Read More from Heidi Stonehill

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