$
Placed at the end of a METAR to indicate that the automated station requires maintenance. The $ symbol means that one or more sensors may be providing inaccurate data. Pilots should treat observations from stations with the maintenance indicator with caution and cross-reference with other weather sources.
RMK AO2 $
RMK $
RMK AO1 SLP135 $
$ stands for "Maintenance Indicator" in the remarks section of a METAR report. Placed at the end of a METAR to indicate that the automated station requires maintenance. The $ symbol means that one or more sensors may be providing inaccurate data. Pilots should treat observations from stations with the maintenance indicator with caution and cross-reference with other weather sources.
$ appears in the remarks (RMK) section at the end of a METAR observation. The remarks section follows the main body of the METAR and provides additional details about the observation that don't fit into the standard coded format.
Here is an example: "RMK AO2 $". This appears in the remarks section and indicates maintenance indicator information as part of the weather observation.