What is feels like temperature and why it is different

Extreme heat and cold are dangerous for human health, especially if you are outdoors for a long time. In this article, we will analyze what to pay attention to when preparing for outdoor activities, how to avoid frostbite and hypothermia, and why it is important to understand the difference between the temperature and the “feels like temperature".

What is the air temperature in general?

Air temperature is the physical quantity expressing how hot or cold the air is. It is one of the main characteristics of the state of the atmosphere together with wind, humidity, atmospheric pressure, clouds, and others. It’s unstable, constantly changing at every point of the planet, and depends on different factors:

the angle at which the sunlight reaches the Earth;
the distance between the Sun and the Earth;
the type of the surface (plain, rough, dark or light, etc.);
cloudiness.

How does the air temperature “work”? The air is not heated by the Sun itself, rather it absorbs the heat from the surface of the ground. Different types of surfaces absorb, store and reflect solar energy in different ways. The darker the color of the surface, the more heat it retains and, accordingly, heats up the atmosphere more. The closer the angle at which sunlight reaches the Earth to 90 degrees, the more heated is the ground and, consequently, the air. And cloudiness is of great importance. For example, clouds act as a blanket at night and can trap heat.

Air temperature is measured in Celsius (ºC), Fahrenheit (ºF), and Kelvin (K).

Learn more about air temperature in Windy.app Meteorological Textbook (WMT) for better weather forecasting.

Photo: mads-schmidt-rasmussen / unsplash

What is the difference between temperature and feels like temperature?

In many weather forecasts, we see not only air temperature values, but also a “feels like temperature” or a "weather feels like". It may differ from the regular temperature — as if a special employee of the weather station goes out in the morning and describes what he or she feels.

Air temperature is a real physical quantity that is measured with a thermometer in a special ventilated meteorological booth. And the “feels like temperature” is an indicator that includes not only air temperature but also air humidity and wind speed.

That is, the "feels like temperature" is the temperature that a person dressed for the season feels.

How feels like temperature is calculated? Is there any formula?

There is no single way to calculate feels like temp, and there is no special feels like temperature calculator. Different meteorological services and mobile applications include different sets of indicators in the calculation. But there are two different indices for determining the "feels like temperature" — the Heat Index and the Wind Chill Factor.

The Wind Chill Factor is the lowering of body temperature due to the passing-flow of lower-temperature air. It shows how much heat the human body loses depending on the wind speed. The higher the wind speed, the faster the surface cools. Humidity is not taken into account in the calculation. The Wind Chill Factor is always lower than the actual air temperature.
The Heat Index is used instead when the feels like temp is higher than the actual air temperature. The Heat Index shows how humidity affects the "feels like temperature" in hot weather. The higher the humidity, the higher the perceived temperature appears than the actual temperature.

Photo: simon-english / unsplash

Why feels like temp is important for wind sports and outdoor activities?

Warm season

When planning outdoor activities during the warm season, it is important to consider the Heat Index. In the heat, the human body sweats a lot, but because of the high humidity, the sweat hardly evaporates. This slows down the cooling process of the body and significantly increases the risk of getting heatstroke. Its symptoms are headache, heart palpitations, confusion, dizziness, dehydration, muscle cramps, nausea, and general weakness.

For example, if you are planning to trail run a distance in the mountains in a new country or region, come there at least a few days earlier so that the body acclimatizes. Reduce your athletic load, exercise in special light clothing, and drink plenty of water. After all, the more a person sweats in hot and humid weather, the more important it is to replenish fluid losses, which directly affect energy levels. If possible, train in the shade — so the body will not heat up from direct sunlight at least.

It is best to switch from active training to quiet activities such as walking or fishing if the "feels like temperature" is high. Better yet, go swimming: being in the water will help the body cool down faster. But the main thing is to put on a hat.

Cold season

When doing sports and outdoor activities during the cold season, it is extremely important to take into account the Wind Chill Factor. Low air temperatures are dangerous for the human body, and this danger is further intensified by an increase in wind speed.

The Wind Chill Factor is especially important when preparing for active winter sports that involve wind. For example, snowkiting. The minimum wind speed required for the kite to rise in the air is 5 m/s for beginners, and advanced riders — 10—15 m/s.

Now imagine that the ambient temperature is -3 °C (26.5 °F) and the wind speed is 10 m/s. In this case, the human body needs to use the same amount of heat as at -11 °C (12.2 °F) without wind.

It turns out that even with a slight cold, but strong wind, you can get severe frostbite or pneumonia if you do not take into account the Wind Chill Factor when choosing clothes and equipment for riding in such weather.

How to get the weather today feels like in Windy.app?

Windy.app has its own feels like temperature formula too, using both indicators depending on the weather conditions. We have a combination of Heat Index and Wind Chill Factor: at temp <50 °F (10 °C) we use wind chill, and at temp >80 °F (26.6 °C) -- Heat Index. And for the average values, we consider wind, also.

To get feels like temperature in Windy.app:

1. Open your favorite or the nearest sport to your current location.

2. Choose Lite Weather profile by an icon of the umbrella right to the weather forecast models on the spot screen.

3. Get feels like temperature for today: