reference|http://artefacts.ceda.ac.uk/badc_datadocs/surface/code.html
short_description|Past weather
wmo_code|4561
long_description|Past weather is defined as weather occurring in the past 6 hours at 00, 06, 12, 18 UTC, and the past 3 hours at 03, 09, 15, 21 UTC.
codeTYPE|S
@| Values
0|cloud covering half or less of the sky throughout the period
1|cloud covering more than half the sky during part of the period & half or less for the rest
2|cloud covering more than half the sky throughout the period
3|sandstorm, duststorm or blowing snow
4|fog or ice fog or thick haze
5|drizzle
6|rain1
7|snow, or rain and snow mixed
8|shower(s)
9|thunderstorm(s) with or without precipitation