car won’t start when it’s hot outside, will start with jump but but puzzeling because battery has full charge
this may be something you’ve tried already but possibly in the heat the battery terminals are expanding just enough to make a difference to how well the battery is getting juice to the rest of the car. possibly just try cleaning the terminals and tightning them up. if that doesnt work you can always take your battery to wal-mart or someplace like that and have it put in a diagnostic machine for free. before you start spending cash on a possibly easy fix. or i believe if you take your car there walmart can also test the draw that the starter is taking. which is another free service they’ll do.
When it won’t start, does it crank over at a normal rate? If it’s turning over slower than “normal” that could be an indicator that the battery is not capable of supplying enough current to crank the engine and keep the electronics sufficiently powered to start the engine.
How have you determined that the battery has a full charge? Voltage is not a good indicator of CAPACITY. A load or electrolyte test (specific gravity by hydrometer) is far better at determining battery health.
Have you removed the battery terminals and checked for corrosion between the post and terminal? Keep in mind that when you “jump” the car, you are connecting directly to the terminals/cables feeding the car. The battery has to deliver current through the post to terminal interface.