The warmer air is the more water it can contain. Outside of the tropics, the easiest way for rain to form is for water to coalesce around ice crystals. Warm air, no ice, no rain this way. Rain also comes when the atmosphere is saturated. One hundred percent humidity equals rain but as the air gets warmer it take a lot more water to reach the rain percentage. You need very warm oceans and/or moist tropical rainforests and the right air convection working together for this to happen. It is obviously a lot more complex than this. Read the Physics of Precipitation or How Does a Raindrop Grow. There is also Precipitation Patterns for a less dense explanation.
Bottom line, hot air tends to be dry air.
Hot dry conditions lead to more wildfires. That is Common Sense 101. Fire, in turn, consumes oxygen and releases carbon dioxide. That is Chemistry 101. This, in turn, increases the ratio of greenhouse gases in the atmosphere while removing the best air scrubbers ever created, plant life. That leads to still more warming which leads to more fires in a classic feedback loop that brings still more drought and more fire. In simple terms...
Fire bad. Tree pretty. ~ Buffy Summers, Buffy the Vampire SlayerMy apologies to rightwing deniers who believe marketing experts and TV clowns over scientists.