How do my hands and feet hurt when it rains?

Rheumatoid arthritis (rheumatism does not cause joint discomfort) is the most likely cause of joint discomfort (including hands and feet and other joints, bilateral joints). Rheumatoid arthritis is an immune functional disease, and its etiology has nothing to do with rheumatism.

Rheumatoid arthritis is unlikely if it only hurts hands and feet (not joints) on rainy days.

When you say "when it rains", I don't know how many times you have recorded that your hands and feet will hurt in rainy days, but never in other weather. There must be a certain amount of statistical data, otherwise it is impossible to judge.