No it has to be done for each map...Maybe several times if you want different weather in different areas as in land2 warm one end snowy the other.
Only you know the size and position of the weather you want.
Only you know the size of the map you are working on.
Use your 1.04 mapping list and a pre written block to start.
It may look daunting at first but it is really quite simple to get something up and working.
Example I want to curse a town with bad weather..... the centre of the town is 2500, 1000
ORIGINAL BLOCK
CREATE_WEATHER_CLIMATE(3, 5, "2831.67,1851.43", 385.833344, 477.500000)
CREATE_WEATHER_CLIMATE_RAIN(3, 0.800000, 0, 80, 0)
CREATE_WEATHER_CLIMATE_TEMP(3, 8.000000, 8.000000)
CREATE_WEATHER_CLIMATE_WIND(3, 0.000000, 0.000000, 1.105375)
EDITED BLOCK
CREATE_WEATHER_CLIMATE(1, 3, "2500,1000", 300, 200)
CREATE_WEATHER_CLIMATE_RAIN(1, 1, 0, 80, 0)
CREATE_WEATHER_CLIMATE_TEMP(1, 40, 40)
CREATE_WEATHER_CLIMATE_WIND(1, 0, 0, 1)
All you should really need to do now is edit line 1 to your position and size.