No question, the worst time to visit the Lake District, known to most Brits as "The Lakes" is August, when it rains. It's just bad luck that the school holidays for most Europeans are in August. Many British children suffer countless ruined holidays, the most rainfall in the UK falls on Langdale, and where do you think the lake water comes from?

May, mid-Sept and October are great times to go and not as crowded as school holidays. Winter is also good, often cold (though not by North American standards - maybe a light dusting of snow) with brilliant blue skies; some hotels and attractions will be closed, but the pubs are open.