Preparing gridded data for GIS from Matlab

I’m looking for the best way to prepare raw data files for import into GIS. I am not a GIS user, but am analyzing data that will be passed to GIS users on our team.

I am performing an analysis in Matlab (but just as easily C++ or Python) for a grid of locations, resulting in a dataset with Latitude, Longitude, and Data (e.g. Hours of sunlight in a day). I could also describe the locations in X,Y coordinates for a stereographic projection with an arbitrary origin.

I’m dealing with polar data (e.g. origin 85S, 30E), so my Lat/Long is not square. X and Y coordinates are.

My intent is to write this data to files that can be directly imported into GIS (ArcMap). I believe this should be formatted as a raster layer. I’d like to include any required metadata to project it properly in GIS. I’m finding it quite difficult to find straightforward information on a format and syntax that would be appropriate.

Does anyone have any ideas or a good reference for data providers?