On Thu, 20 Jul 2017 20:29:24 +0100, Jim S wrote:

On Thu, 20 Jul 2017 12:13:43 +0100, James Wilkinson Sword wrote:

What do you believe weather forecasters mean when they say "40% chance of rain"?

1) It will rain for 40% of the day.
2) There's a 40% chance it will rain at some point.

I googled it and apparently it depends on the forecaster? 1) and 2) are completely different meanings.

Unless there is high pressure stuck over us you can go to 7 UK forecast
sites and get seven different percentages or timings. They all claim to get
their information from the Met Office. I don't believe that all seven have
in-house meteorologists so who makes it up?

If I've been in the same place for 12 hours, and am going to be there for another 12, my watch's barometer is a better guide than the internet forecasts. It takes a reading every minute, so I get a graph of the next 12 hours ish. It doesn't say exactly what the weather'll do, but it's a very accurate guide that it'll get worse or better throughout the day.

--
"I've never claimed to be anything more than a simple person" - Ronald Tompkins, circa 2013.