Forecasters look at data produced by several different weather supercomputers generated over different timescales.
Not all computer models are in agreement about how the finer details of the Christmas forecast will look, but there are some themes now emerging.
The first half of December has been mild and wet, dominated by rain-bearing Atlantic low pressure systems. This general set-up is expected to continue for the next week or so, but there is a chance of higher pressure building into late December, which would bring a drier spell compared to recent conditions.
Whilst temperatures are likely to drop a little, returning to more typical for the time of year, there is no especially cold weather expected at this stage. Overnight frost and fog could well become more of an issue over the Christmas period. Wintry showers cannot be ruled out, especially over high ground in the north, but there are currently no indications of widespread snow.
Forecasting snow in the UK is notoriously difficult, and it is still too early to know for certain whether we will see a white Christmas in 2025.
The festive forecast will become much clearer about five days before Christmas, so keep an eye on the BBC Weather app or website for the latest updates.
