Sunsets

Sunsets as Weather Forecasters

The colours of a sunset are a fairly reliable guide to the following day's weather. There is much scientific truth behind old folklore rhymes such as 'Red sky at night, Shepherd's delight'. The reason is that the rays of sunlight passing through the atmosphere are similar to light passing through a prism. The main sky colours depend on the scattering and reflecting of the rays and the number and size of particles of moisture in the atmosphere.
If the atmosphere grows moister, the particles increase in size and number, scattering the blue rays, so that somebody on the ground sees reds and yellows instead.
The reverse occurs on a fine day when these particles are few and small, giving a blue sky.

How to Read a Barometer

A barometer can be misleading if you look to see only if it is high or low. Sometimes the barometric pressure will be high and the needle will point to 'fair weather' on a rainy day. At other times the needle will point to 'rain' in fine weather. The important thing to note is whether the barometer is rising or falling. Tap the glass and note whether the needle rises, falls or stays steady. Also note any changes in the wind.
    If the barometer is fairly high, but showing a decided fall when tapped, unsettled weather is approaching, especially if the wind is backing (anti-clockwise) to south or southeast. If the barometer is low, but the needle jumps up when you tap the instrument, and the wind has veered (clockwise) from southeast to northwest, expect clearing skies and sunshine.
    A rapid rise means the weather improvement will only be temporary.
    Sometimes the barometer will fall slightly without any rain coming. This usually denotes freshening winds, and any improvement will not last long.
Above-right is a cut-away drawing of a domestic (aneroid) barometer.

How it works : The aneroid barometer is the type often seen in homes. It contains a small metal box from which most of the air has been removed. The box has a flexible lid to which a lever is attached. Changes in air pressure move the lid and its lever. The lever is connected to a pointer, which it moves across a dial to indicate air pressure changes, and thus show weather variations.

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How to Read a Barometer
A barometer can be misleading if you look to see only if it is high or low. Sometimes the barometric pressure will be high and the needle will point to 'fair weather' on a rainy day. At other times the needle will point to 'rain' in fine weather. The important thing to note is whether the barometer is rising or falling. Tap the glass and note whether the needle rises, falls or stays steady. Also note any changes in the wind. If the barometer is fairly high, but showing a decided fall when tapped, unsettled weather is approaching, especially if the wind is backing (anti-clockwise) to south or southeast. If the barometer is low, but the needle jumps up when you tap the instrument, and the wind has veered (clockwise) from southeast to northwest, expect clearing skies and sunshine. A rapid rise means the weather improvement will only be temporary. Sometimes the barometer will fall slightly without any rain coming. This usually denotes freshening winds, and any improvement will not last long. Above-right is a cut-away drawing of a domestic (aneroid) barometer.
How it works : The aneroid barometer is the type often seen in homes. It contains a small metal box from which most of the air has been removed. The box has a flexible lid to which a lever is attached. Changes in air pressure move the lid and its lever. The lever is connected to a pointer, which it moves across a dial to indicate air pressure changes, and thus show weather variations.