There are two methods for calculating the tilt angle for solar panels.
Optimum tilt angle for solar panels sydney.
Both of these angles require latitude degrees.
Whatever your latitude is you can subtract 15 from it to calculate the angle for summer.
However the panels can be installed anywhere between 10 to 35 deg with negligible efficiency loss.
Perth latitude 32º.
For example if you reside in sydney a roof pitch of 34 would be considered ideal as this is equal to the latitude angle 33 86 of the nsw capital.
The orientation of the panels and the angle they are tilted will have a greater effect on annual energy production.
To lean toward more production in the summer tilt your panels at your latitude minus 10 15.
To optimize overall production year round tilt your panels at your latitude.
In every capital except darwin output is maximized when the solar panel tilt is at least a few degrees less than the latitude.
This means that for best results the roof pitch of your property should ideally be equal to the latitude angle with the panels mounted at the same angle as the roof.
Most australian homes have a roof pitch of 20 to 30 which is considered optimum for maximizing solar power generation.
Sydney latitude 34º.
Similarly you can calculate the angle for winter by adding 15.