The BBC weather forecaster Jay Wynne confessed to the Radio Times that he often stays awake until dawn to look at the sky and see if his weather reports are correct (Times2, July 6). He is particularly interested in what sort of cloud is around. “I have been known to drive around after night shifts, waiting for the sun to come up,” said Wynne. “At night, it’s difficult to tell what kind of cloud there is on satellite pictures, so I like to see if I was right.”
Looking at the sky at dawn was also used for folklore forecasting, as the famous saying goes:
Red sky at night, shepherds delight Red sky at morning, shepherds take warning.
It was such good advice that Shakespeare used it in Venus and Adonis:
Like a red morn, that ever yet betoken’d Wreck to the sea man, tempest to the field, Sorrow to shepherds, woe unto the birds, Gust and foul flaws to herdmen and to herds.
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Generally speaking, red sunsets in the UK indicate good weather the following day. A red sky at sunset indicates clear skies to the west — the direction most of our weather comes from.
The red colour at sunset is from dust in the sky that tends to scatter most colours of light more than red. In the morning, a red sky may come from dust ahead of approaching bad weather sweeping in from the west. Or the red dawn sky can be caused by high-altitude clouds scattering the light at the edge of an approaching weather front.
Another saying also points to cloudy dawns:
Evening red and morning grey, Two sure signs of one fine day.
This could mean that a morning grey sky as the sun rises in the east can often indicate that rain has already passed through as the weather sweeps from the west. Another possible interpretation is that morning grey refers to early morning mist, fog or shallow low cloud, all of which tend to form on clear, calm nights but soon disperse after sunrise on a fine summer day.