- March comes in like a lion, and goes out like a lamb – the month of March usually starts with cold, unpleasant weather, but ends mild and pleasant. (Either part of the proverb can be used alone.)
- To be as mad as a March hare (old-fashioned) – to be crazy ‘This woman was dancing in the road and singing very loudly – I thought she was mad as a March hare’.
- Beware the Ides of March – from Shakespeare’s Julius Caesar, 1601. ‘Beware the Ides of March‘ is the soothsayer’s message to Julius Caesar, warning of his death.
The Ides of March didn’t signify anything special in itself – this was just the usual way of saying “March 15th”. The notion of the Ides being a dangerous date was purely an invention of Shakespeare’s; each month has an Ides (often the 15th) and this date wasn’t significant in being associated with death prior to 1601. Source: phrases.org
- March was originally the first month of the Roman calendar until Julius Caesar changed it to be the third one.
- Farming superstition held that if the first three days of March were rainy, it would mean a bad crop later in the year.
- There is also an equinox around the 21st March, where day and night are equal around the world.
And here is a nice blog piece about March proverbs from around Europe