Multiple complex queries

[Malcolm Rook]

I am in the process of moving from SQL Server 2005 to MySQL.
I have a database of weather data (5 temperatures, pressure, humidity, light level and 4 wind speed and direction parameters) which is logged every minute. (The SQL database table currently has over 2 million entries, indexed on the reading date/time).
When querying the table for display, the timescale can be 6, 12 or 24 hours or week, month or year. The data needs to be averaged or summed for various periods to give 360 values along the time axis.
I can get the data by issuing a query for each time slot to return the avreaged/summed data but this means issuing 360 queries and is slow, taking about 30 seconds to complete.
Does anyone know of a more elegant, and faster, way to achieve this?