Common Weather Folklore and Proverbs

"The higher the clouds, the finer the weather."
When there are thin, wispy clouds very high up in the air, the weather is very likely to be nice.

"Clear moon, frost soon."
When there aren't any clouds in the sky and you can see the moon at night, the earth cools quickly because there is no coverage. Therefore, the temperature will drop, creating frost in the morning.

"When clouds appear like towers, the Earth is refreshed by frequent showers"
Clouds that look like cauliflower or castles are most likely forming weather inside. If the clouds grow and begin to look gray, there is a big chance of a thunderstorm appearing.

"Rainbow in the morning gives you fair warning."
If you see a rainbow in the morning when you wake up, it means rain is coming in from the west.

"Ring around the moon? Rain real soon."
The 'halo' around the moon is caused by an incoming warm front forcing high, thin clouds to get lower, and thicker. The ice crystals within the clouds are then reflected by the moon's light forming the halo you see.

"Rain foretold, long last. Short notice, soon will pass."
If it looks like it is going to rain because of overcast for days on end, but it hasn't yet, then when it finally does rain it will last for hours. When the rain is unpredicted, it won't last for long.

" No weather is ill, if the wind be still."
There shouldn't be any precipitation if the wind is calm or still because they are usually found towards the middle of a high pressure system or air mass. Whereas precipitation is usually in the boundaries of air  masses.

"A rainbow in the morning is the shepherd’s warning. A rainbow at night is the shepherd’s delight."
Rainbows in the morning mean rain is coming soon, but a rainbow at night mean the rain has passed.

"If the moon's ace is red, water ahead."
A low pressure front bringing moisture is pushing dust ahead, which causes the red colour.

"If birds fly low, then rain we shall know."
Air becomes 'heavier' when the air pressure drops. This is why birds will fly lower to the ground, and a lower air pressure means that there will most likely be bad weather such as rain or snow.

http://www.almanac.com/content/weather-predicting-do-it-yourself
http://cksimpsonwx.blogspot.ca/2013/03/myth-no-weather-is-ill-if-wind-is-still.html
http://www.essortment.com/weather-forecasting-history-accuracy-21151.html
 http://www.farmersalmanac.com/weather/2009/02/23/top-4-folklore-favorites/