St. Paul's Day was used for prognostication of the weather for the coming year. Similar to Candlemas (or groundhog day), the farmers looked at certain things that occurred on the 25th of January to tell them what would come in the future year.
In Lloyd's Diall of Daies, published in 1590, it was suggested that:
If it be a fair day, it will be a pleasant year.
If it be windy, there will be wars.
If it be cloudy, it doth foreshow the plague that year.
According to the Shepherd's Almanack of 1676, it was suggested that:
If the sun shine, it betokens a good year
If it rain or snow, indifferent
If misty, it predicts great dearth
If it thunder, great winds and death of people that year.
Willsford, in his book, Nature's Secrets, published in 1658, provided the following verses:
If St. Paul's Day be fair and clear,
It does betide a happy year;
But if it chance to snow or rain,
Then will be dear all kind of grain:
If clouds or mists to dark the skie,
Great store of birds and beasts shall die;
And if the winds do fly aloft,
Then wars shall vex the kingdome oft.