I think it's important that part of the north England is included, or you won't have a CET that's anything like representative for several million people, and it would be artificially high.
Let's remember what the CET is: a very long-term record of temporature across three stations dotted around the country. It doesn't seek to give a totally accurate representation of the average temperature across every square mile of the country, but provides a comprison for year-on-year analysis.
Originally Posted by: Saint Snow