Rare is the outdoorsperson who is not happy to discuss weather omens – even if it is only to pour scorn on some theory about thick apple skins foretelling a hard winter. They don’t.
As a general rule, longterm or seasonal forecasting tricks are worthless. Anything that claims to be able to predict weather more than a few days out can nearly always be safely ignored. But some short-term techniques do have value.
There are many reliable weather clues to be found during the day, especially using the clouds. But it’s worth knowing that there are changes that can be spotted before even the clouds offer any worthwhile insights and one of them is in the night sky.
Stars twinkle. The narrow beam of starlight is buffeted by our atmosphere, so it has been on something of dodgem ride by the time it reaches our eyes. This journey through the air creates the twinkling, or ‘scintillating’, to give the effect its formal name.
Stars near the horizon will twinkle more than those above our heads, because they pass through more of our atmosphere before reaching us. The twinkling also increases when humidity rises, the air pressure drops and there are strong pressure gradients in the atmosphere – all signs of worsening weather.
The easiest way to get a feel for this is during a dry spell. Study the stars of one constellation for a few clear nights in a row until you get a feel for how much they twinkle when things are settled. The fair weather won’t last forever and when you notice your stars twinkling much more than you are used to, rain is on its way.
Check out this page for more on weather lore.
Or for more on fronts, you might like ‘When a Low Pressure Goes Through‘.