Morning of the 20th was foggy and below freezing.
Not a lot to add, weather was the same here.
[update] Oh yes there is!
This overlay plot is the result of running a crude data extract program on the .png, was written first for the Lunar data work. Almost exact but could do with refining. Looks like it is inside 2%
Better I hope, a spreadsheet containing the data is zipped here.
[/update]
Archive of the data here (includes sky photo thumbnails)
Archive for the following day is here, different again
I thank Chilbolton Observatory for their data
http://www.stfc.ac.uk/Chilbolton/weather/24987.aspx
Post by Tim Channon
[...] chilbolton-freezing-fog [...]