When Is The Hottest Part Of The Day

When Is The Hottest Part Of The Day?

When is the hottest part of the day?  Ask anyone this, and they will be quick to say noontime or 1 pm is the hottest time of the day.

Determining the hottest time of day largely depends on the time of year.  It also depends on where you are located on this planet earth.

The Earth receives the sun at different times of the day, creating a variety of time zones.  The rays from the sun heat the planet the same way a burner on a stove boils water. Even though you set the burner on high fire, it takes a while for the water to boil. The same concept is valid with the temperature of the day.

What Is The Hottest Part Of The Day?

There is a misconception with most people believing that the warmest time of the day is noon. It may feel hotter at noontime simply because we are getting the most energy from the sun at that time.

However, it is different from the planet Earth.  As the day gets hotter, the Earth stores the incoming energy or heat throughout the day. The longer the sun is out, the hotter the air becomes.

What Is The Hottest Part Of The Day

Temperatures keep climbing as long as the Earth receives more incoming heat than it released back into space. The re-radiation takes place later, making the hottest part of the day between 3 pm and 6 pm during the summer.

During the morning hours, the temperatures warm very quickly because of the mixing of 2 air masses.  Over the night, the cooler air sinks to the valley from the mountains.

As the sun rises in the morning, solar radiation starts to heat the ground. The 2 air masses’ difference in temperature creates turbulence which results in a quick warm-up.

What Determines The Hottest Time Of The Day?

The hottest time of day is determined by some factors that include,

Direct Sunlight

The sun is at its highest point, approximately at noon. The sun’s high point is when it gives the Earth the solar noon, the most direct sunlight.

At this point, a sunburn will quickly occur in the shortest amount of time due to the direct sunlight.  At this time, the sun’s radiation is the strongest; however, even though it is, its temperature is still not the hottest.

Diurnal Cycle

The diurnal cycle is the rotation of the Earth on its axis, creating night and day.  The diurnal cycle is the effect that creates a delay in temperature increase on the Earth’s surface known as the thermal response.

Between the times the sun provides the Earth with the most direct sunlight and when the temperature rises, the National Climatic Data Center estimates a 3 to 4-hour delay.

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Thermal Response

This process begins at solar noon when the surface of the Earth starts to heat. As long as the Earth receives more heat than it sends to space, the temperature continues to climb.  Generally, there is a delay between the solar noon and the hottest time or the thermal response.

During the summer, the hottest part of the day is usually between 3 pm and 4:30 pm, depending on the wind speed and the cloud cover.


The hottest part of the day is determined by different variables. Depending on the time of the year, if your part of the country recognizes daylight savings time, the hottest part of the day will be increased or decreased by an hour.

The season will also make a difference because of the climatic changes occurring during the winter. Many times, the cold fronts decrease the temperature all day long during this time of the year.

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Your location also determines what time of the day is the hottest. In this winter weather, the hottest part of the day can be in the early morning.  A cold front can later follow in the afternoon, cooling down the surface of the Earth. The climatic changes can affect one part of the country or the Earth, while another is not affected.

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Important Information To Note

Although it is easy for most people to assume the hottest time of the day occurs when the sun is projecting the most beams onto the Earth, this is not the case.

As with other concepts that center around the idea of heat, this is not a process that unfolds quickly.  It also takes time to reach its warmest temperature.  Thermal response and solar radiation make it easier to understand the temperature patterns and why these behave in such a manner.

Somehow many suggest that the coldest time of the day is late-night, around midnight, but this is not the case. Even though the sun rises early morning, the temperatures remain colder at this point as the Earth is yet to warm up.

Both the hottest part of the day and the coldest time are affected almost by the same factors of time and the radiation process.

Important Information To Note

Surprisingly the coldest time of the day happens way later than many would expect, and as we have mentioned, it occurs shortly after the hottest time of the day.

There are specific factors that make it hard to identify a particular time of the day, especially when it is the coldest. However, it is likely to be around one to two hours after the hottest time of the day.

There are scientific explanations behind the delays of temperatures both as they rise and they fall.  It is important to note that differences can be witnessed depending on your location and the weather pattern that you experience.


Science is complicated, and only with many studies can we break it down to our level of understanding.  The information has broken it down so well to help every person understand it and relate to it the best way they want to.

If you are a gardener and want to know when is the hottest part of the day so that you don’t transplant at that time, now you do. And if you are a hiker and want to avoid the hottest part of the day outdoors, now you know how to read your weather.