Why is July the hottest month of the year? | Climate News

EXPLAINER

The world faced its 12th consecutive month of historic heat, with this summer on track to be among the hottest ever.

Although summer has just begun in the Northern Hemisphere, heat waves have already hit many parts of the world, including the United States, Mexico, Europe, the Middle East and South Asia.

The extreme heat has led to more than a thousand deaths, urgent health warnings and school closures.

July is historically the hottest month of the year, where in parts of the Northern Hemisphere temperatures regularly exceed 40ºC (104ºF).

According to the UN World Meteorological Organization (WMO), July 2023 was the hottest month on record, probably the hottest in at least the last 120,000 years, with this year already in to accompany to be one of the hottest yet.

Axial tilt and the summer solstice

The Earth is tilted 23.5 degrees on its axis as it orbits the sun.

This results in varying amounts of sunlight at different times of the year, which creates the changing seasons.

Astronomical summer begins at the summer solstice, which occurs around June 20 or 21 in the Northern Hemisphere and around December 21 or 22 in the Southern Hemisphere.

This is the day when the sun reaches its highest point in the sky at noon, resulting in the longest day and shortest night of the year.

The part of Earth that receives the most direct sunlight is 23.5 degrees above the equator, known as the Tropic of Cancer.

This line passes through Mexico, Bahamas, Egypt, Saudi Arabia and India, among other countries, contributing to very hot summers.

Summer in the Northern Hemisphere

Although half of Earth’s landmass experiences summer from June to September, about 90% of the world’s population lives in the Northern Hemisphere, where these months coincide with more direct sunlight and longer daylight hours.

In cities further north around the Arctic Circle, the sun does not set between the end of May and the end of July, in a phenomenon known as the midnight sun.

On the other hand, during the winter months, these same locations experience a polar night, where the sun remains below the horizon between the end of November and the end of January.

Why is afternoon hotter than midday?

During the summer months, more energy from the sun is absorbed by the ground, which warms the surrounding air and leads to higher temperatures.

The time delay between heating and release is known as the seasonal delay.

The Earth’s surface, especially large bodies of water like the oceans, which comprise 70 percent of the Earth’s surface, takes time to absorb heat from the sun and subsequently release it.

This explains why the peak temperature of the day occurs in the afternoon and not at midday, and why July, and not June, typically records the highest average temperatures.

How to stay cool this summer

As summer temperatures rise in many regions of the world, with some even breaking historic heat wave records, staying cool becomes crucial. Fortunately, there are effective methods for beating the heat, whether you have access to air conditioning or not.

Here are 10 tips to help minimize your risk of heatstroke: