How to manage script for average data calculation in selected bin (lat,lon)?

I have a set of data with each row representing a series of observations taken at a particular point with 0.25 deg interval started with 0 to 14 latitude and 95 to 126 longitude. There are 3 column where 1st and 2nd column represent latitude and longitude respectively, while the 3rd column is the data. The data needs to be average for selected bin with both latitude and longitude 0.5 bin-averaged grids. For example, I want to average data bin from 0 to 0.5 lat and 95 to 95.5 longitude. How would I go about doing this?