Both colic and witching hour begin at around 3 weeks of age and tend to resolve by 3 - 4 months of age, however, they are markedly different in other ways. Colic is typically defined as a baby who cries for 3 or more hours a day, 3 or more days a week, for 3 or more weeks at a time. The crying is often far more intense in colic than in witching hour and a colicky baby is far more resistant to soothing than a baby who is experiencing witching hour. A colicky baby will also often exhibit physical signs of discomfort like back arching and tensing of limbs which are rare in a witching baby hour.