bug#19401: 25.0.50; metar.el (metar-convert-temperature) wrong type argument stringp nil

[Mark Oteiza]

Hi,

I recently got the following from metar.el using KPHL:

Debugger entered--Lisp error: (wrong-type-argument stringp nil)
  intern(nil)
  metar-convert-temperature("M01")
  metar-dewpoint("KPHL 172054Z 28015G23KT 10SM BKN046 10/M01 A2993 RMK AO2 PK 
WND 28029/2044 SLP135 T01001006 53013")
  metar-decode(((21649 60776) . "KPHL 172054Z 28015G23KT 10SM BKN046 10/M01 
A2993 RMK AO2 PK WND 28029/2044 SLP135 T01001006 53013"))
  metar(1)
  funcall-interactively(metar 1)
  call-interactively(metar record nil)
  command-execute(metar record)
  execute-extended-command(nil "metar" nil)
  funcall-interactively(execute-extended-command nil "metar" nil)
  call-interactively(execute-extended-command nil nil)
  command-execute(execute-extended-command)