Weather manipulation for geopolitical pressure/conflict purposes is expressly a war crime. Which means that, when they made such a rule, it was a real enough possibility to list and bring it up. And that was a while ago.

Simple cloud seeding is definitely a thing, Japan did it to ensure no rain during their Olympic opening ceremonies (with permission from the UN). But that's not temperature control, it's just forcing it to rain earlier so it doesn't later. Changing temperatures by 5 degrees is such a colossal amount of energy that it isn't practical: Ask any climate change skeptic OR alarmist, how much fossil fuel, how much energy, is needed to even move the needle one degree. The entirety of the human race's energy output for decades.

And all that hot air doesn't stay in one place. Air moves. Your fridge doesn't work nearly as well open, as it does closed, and your fridge only had one wall/segment exposed to open air when open, not the complete open air of a coastline and several country borders.