Hugor, I too have noticed in the last couple of weeks or so the forecasts have kept changing quickly, promising ‘sun tomorrow’ but then by the next morning it’s changed to heavy rain all day! I think we’re just going through a period of particularly unpredictable weather, which doesn’t fit into the computer models that the Met Office and others are using.
Overall the Met Office and the BBC are pretty reliable. I particularly like the map at the bottom of the BBC 24 hr or 5 day forecast for your town, which shows the rain passing through, so you can make a good guess of when its going to rain on you.