St. Swithin's day if thou dost rain
For forty days it will remain
St. Swithin's day if thou be fair
For forty days 'twill rain nae mair.
Believe it or not, the above constitutes a pretty good scientific hypothesis in that it makes a (fairly) clear and testable prediction: if it rains on St. Swithin's Day, it will rain for the next 40 days; if it doesn't rain on St. Swithin's Day, it won't rain any more.
Today (15th July) was St. Swithin's Day, and it pissed ropes (as they say in France).
Let us test this particular scientific hypothesis…
Postscript (15-Jul-04): A-ha! It's stopped raining! Hypothesis well and truly falsified!