To make the ecosystem balance...
If it doesn't rain, then how will the plants and other organism survive? We need water for irrigation, water supply, and other uses of it.
And if the sun doesn't shine much, then how will the organisms and others also survive? We uses the sun's light to make our clothes dry, or converting it into energy, source of nutrients, and others.
We need climate/weather change in order to survive.
Not too much and not too less