Global warming is a hotly debated topic these days. Long term weather forecast is doomed to fail due to Chaos theory implications which causes the output to depend sensitively on the initial input. So a mathematical model formulated for such a prediction is fraught with its limitations.
Vedic astrology presents some useful techniques to time the heightened rainfall activity. Bhanu Madhya - as the phrase means literally - is caused when Sun is hemmed between Venus( a cool, watery planet) and Mercury (a fickle minded planet implying the unpredictable nature of the weather forecast). That sort of indicates the chaotic nature of climate change in essence. Presently, Tamil Nadu had an unseasonal shower which may be explained as below:
Sun is in sagittarius flanked by Venus in Scorpio(a watery sign) and Mercury advancing towards Chara rashi of Capricorn(ruler saturn indicating some airy activity like cyclonic storm and low pressure trough). Sagittarius is south-easterly sign denoting Tamil nadu and Mars is the ruler of scorpio whose devata is Murugan indicating Tamil nadu.
So that prima facie has some interesting correlation which need to be delved deeper into.