A routine observation made at an aerodrome throughout the day.  METAR observations are made (and distributed) at intervals of one hour or, if so determined by regional air navigation agreement, at intervals of one half-hour. <br /></p><p><br /></p><p>The information contained in METAR and SPECI is identical. SPECI is issued when conditions merit a non-routine report on conditions at an aerodrome.<br /></p><p><br /></p><p>METARs are a routine report produced for dissemination beyond the aerodrome of origin, and are mainly intended for flight planning, VOLMET broadcasts and D-VOLMET.<br /></p><p><br /></p><p>See Annex 3 Table A3-2<br /></p>