Heat Wave: A prolonged period of abnormally hot weather.
In New York, a heat wave is defined as at least 3 consecutive days at or above 90 degrees Fahrenheit (or 32 degrees Celsius), and they typically occur in July & August. Besides being uncomfortable, heat waves create other health & environmental problems - especially in urban areas where concrete and less vegetation intensify the effect (known as the heat island effect).
Choose your specific issue related to heat waves below to learn more: