With a bit of luck the above image will give the next 7 days weather for London - at the point at which you look at this blog entry. At the moment it appears to be turning coldish. Obviously the image will change with the GFS forecasts from which it is developed.
The good news for the government is that it seems that although December will be slightly colder than average it won't be a really cold month.
The following gives various 16 day predictions for the weather at a pressure height of 850 hectoPascals.
Remember that the further in the future you go the less reliable the predictions are.