In reply to Heike:
Rainfall radar is clear. There's a bunch of weather stations + webcams that give you the current conditions here:
https://www.cumbria.gov.uk/roads-transport/WeatherStations/default.asp
There's a UK wide list of weather stations at:
http://www.weathercast.co.uk/world-weather/weather-stations.html
There's weather station data for various places in the Lakes, Keswick, Blencathra, Shap, Penrith (Newton Rigg), Kendal (Levens Hall) etc just zoom in on the map on the main page to see what locations have data. Keswick is at:
http://www.weathercast.co.uk/world-weather/weather-stations/obsid/3212.html
You'll get the current observations and the previous 5-6 days so can get an idea of how wet it's been, temperatures etc etc.
It's a site that's well worth knowing about in winter as there's stations on Aonach Mor, Cairngorm and The Cairnwell etc which means you can check temperatures, dew point, precipitation etc etc and take a punt on where might be frozen etc.
Post edited at 11:13