High and Low Temperatures: What Time Do They Happen?

Illustration of clouds and red arrow symbol against blue background
High temperatures occur in the afternoon. Low temps happen in the pre-dawn hours. Endai Huedl / Getty Images

High and low temperatures are the most checked weather within weather forecasts. Together they tell you how warm and cool the air will be during a 24-hour period. The daily maximum temperature, or high, describes how warm you can expect the air to be from 7 AM to 7 PM. While the daily minimum temperature, or low, tells how much the air is expected to cool overnight from 7 PM to 7 AM.   

High Temperatures Don't Happen at High Noon

Think high temperatures occur at high noon when the sun is at its highest elevation in the sky?

Think again!

Much like how the hottest days of summer don't happen until after the summer solstice, high temperatures don't happen until the late afternoon -- typically 3 to 4 PM local time. By this time, the sun's heat has built up since noon and more heat is present at the surface than is leaving it. After 3 to 4 PM, the sun sits low enough in the sky for the amount of outgoing heat to be greater than that incoming, and so temperatures begin to cool. 

How Late at Night Do Lows Happen?

Just how long after 3-4PM will temperatures be at their coolest? 

While you can typically expect the air temperature to drop during the evening and nighttime hours wear on, the lowest temperatures don't tend to happen until just before sunrise. You read that right. The coolest part of the day isn't necessarily near midnight!

This can be quite confusing, especially since the low is often listed along with the word "tonight." To help make it a little clearer, consider this.

 Let's say you check the weather for Sunday and see a high of 50°F (10°C) and a low of 33°F (1°C).The 33 degrees that's displayed is the lowest temperature that'll occur between 7 PM Sunday evening and 7 AM Monday morning.

To summarize all of that... the high temperature represents the afternoon temperature, and the low is the temperature for the early, pre-dawn morning (think of it as your "wake-up" temperature).

Highs Don't Always Happen During the Day, Nor Lows at Night

We've talked about the times of day when high and low temperatures occur 90% of the time, but it's important to also know there are exceptions to this. 

As backward as it sounds, sometimes the high temperature for the day won't actually happen until late in the evening or overnight. And likewise, the low can happen during midday. One time of year you'll see this is during the winter season. In winter, a weather system may move into an area and its warm front sweep across a region late in the day. But by the start of the next day, the system's cold front then enters and sends the mercury dropping throughout the daytime hours. (If you've ever noticed a downward-facing arrow next to the high temperature in your weather forecast, this is what it means.) 

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Means, Tiffany. "High and Low Temperatures: What Time Do They Happen?" ThoughtCo, Jan. 8, 2018, thoughtco.com/high-and-low-temperature-timing-3444247. Means, Tiffany. (2018, January 8). High and Low Temperatures: What Time Do They Happen? Retrieved from https://www.thoughtco.com/high-and-low-temperature-timing-3444247 Means, Tiffany. "High and Low Temperatures: What Time Do They Happen?" ThoughtCo. https://www.thoughtco.com/high-and-low-temperature-timing-3444247 (accessed January 23, 2018).