On average a chilly spell around Christmas?

[Len]

There is an interesting dip in the 30-yr average of daily max. temperature in December around Christmas in Wembury. A bit below the normal decreasing temperature for December. This is a little bigger than the other variations above and below the trend line at other places along the time series. One can only speculate about the reason. Surely nothing to do with Santa and people generally at home celebrating?

Len

Wembury, SW Devon