Islip experiences a moderate climate with distinct seasonal variations. Winters are cold and often frosty, with temperatures frequently dipping below freezing from January to March. As spring arrives in April and May, temperatures rise gradually, allowing for mild days and cool nights. Summers bring warm to hot conditions, with July and August being the hottest months, while September and October experience a gentle decline back towards autumnal temperatures. The colder winter months return by November and December, bringing crisp air and occasional frost.