In ArcMap, right-click in the map to access the data frame properties. In the properties UI, select the Coordinate System tab. In the search box, type 4326 and click search icon. The box below should highlight WGS 1984. Okay the dialogs.
The data frame is now using WGS 1984, a geographic coordinate system.
The status bar at the bottom of the data frame may still show meters. If it does, open the data frame properties again, select the General tab. Set the display units to decimal degrees and okay a dialog.
If you want to save a layer in WGS 1984, try right-clicking the layer in the table of contents and select data, export data. In that dialog, set it to use the data frame's coordinate system. I'm not sure if this will for NetCDF data.