Why do you think that data from bom.gov.au costs $90 per city? I was able to download data from them for free. For example, here's a link to climate data for the SYDNEY (OBSERVATORY HILL) observation site:
http://www.bom.gov.au/climate/averages/tables/cw_066062.shtml
You can filter and sort the table in various ways directly on the webpage, and download it in csv or pdf format.
However since the data is available for individual points, I don't think it meets your "one minute" requirement. It would have to be a raster with one minute (1/60 of a degree) resolution. You could download data for many weather stations and interpolate it in GIS software.