How do fire ants know...
 

... to start building up their mounds for insulation starting a day before cold arrives?

Farmers Almanac?? Just guessing.

fire ants will not get near bbq ashes or any campfires ashes! ashes will run them out of the area

They look at the Weather Channel?

They are boring for new season and winged one fly away.

An interesting read about Fire Ants.

Fire Ant Facts | Mississippi State University Extension Service


During cold, wet weather fire ants tend to maintain their colonies high above ground—to keep brood out of water logged soil and to take advantage of solar heating.
During hot, dry weather fire ants tend to maintain their colonies below ground—to take advantage of cool, moist conditions.
Extract from above report.