The low temperature you see on our 10-day forecast pages is valid for the overnight period (7pm – 7am local time) following the day in which the temperature is displayed. Because the time at which the lowest temperature occurs is usually around sunrise, the low is technically during the 24-hr calendar day for the following day.
e.g., the Low you see in the Tuesday display is the lowest temperature in the period between 7pm Tuesday and 7am Wednesday. The time at which that low temperature occurs is typically closer to that 7am hour.
I hope that helps. Thanks for contacting us with your question.