+
+7. What values are valid for a --headers list?
+----------------------------------------------
+The default set it uses if you don't override it yourself on the command
+line or in configuration is as follows::
+
+ heat_index
+ precipitation_last_hour
+ relative_humidity
+ sky_conditions
+ temperature
+ weather
+ wind
+ windchill
+
+These are a case-insensitive match against the start of lines in a
+decoded METAR up to the first colon (:) with underscores (_) replaced by
+spaces. You can see the full METAR for a given condition report by
+passing --verbose or by observing one directly (perhaps by looking in
+your *datacache* directory). Unfortunately I haven't found any proper
+specification for the decoded METAR format used by the NWS so know of no
+comprehensive list of what lines might appear.