Causes of temporary finger weakness?

Consider: A migraine aura, prior to headaches; a true transient ischemic attack due to blocked blood flow; a transient nerve compression at wrist, elbow, or neck; a problem with nerve and muscle connections, such as myasthenia. If an ongoing problem see your doctor.

weakness of the : Intrinsic muscles of the hand, stiffness in joints, tendons or ligaments, nerve issues, joint pain from arthritis or trauma, fracture, dislocation , age, carpal tunnel, ulnar nerve lesions, poor wrist mechanics , diabetes, cold intolerance and finally just pain all can contribute to the feeling that the hand or fingers are "weak".