If what you tell me is not exactly right, it is inaccurate. If you measured the amount of rainfall incorrectly, your data about the climate would be inaccurate.
Accuracy means being very precise and getting the information right. When something is inaccurate, it is the opposite of exact. If you get a question wrong on a test, your teacher will not say, "You, sir, are inaccurate," she'll just say you are wrong. She might also explain that your inaccurate methodology led to an inaccurate response.