How to measure the level of sunlight?

The Sun plays a huge role in our daily lives, as you may have noticed. But have you ever tried to measure the level of sunlight or sunshine in a place? This is less likely! Let's find out together what the term "sunshine duration" refers to, how it is calculated, how you can find out about it, and for what purposes. 1, 2, 3, Sun!

What is the level of sunlight? (according to your national meteorological service)

The level of sunshine has something to do with the sun, you may have guessed… but how? What exactly does this mean? This is important to establish before going any further!
When a portion of the earth's surface is exposed to direct sunlight in such a way that the objects present generate shadows, this is called sunstroke (nothing to do with the last time you were ill during a heatwave… except for the duration of exposure to the sun!) A threshold is established: the sun’s sunshine must then be greater than 120 watts per square metre of surface.
According to this rule, it can be said that from this level of sunshine, "there is sunshine".

This is how meteorological services sets the basis for the level of sunshine. But your national weather institute goes further when it comes to sunshine duration, another name for the level of sunshine.

The duration of sunshine varies according to several criteria according to meteorological services:

  • Astronomical criteria: this is the time at which the sun rises and sets;
  • Geographical criteria: this refers to the topographical environment (notably the relief) of the land surface that is observed;
  • Weather criteria: "The evolution of the cloud cover of the sky, a somewhat nebulous notion;
  • Other less important factors such as the passage of moving objects.

The level of sunshine is measured by the duration of sunshine, the unit of measurement being the minute (or hour).

Get a clear and precise view of the number of hours of sunshine during the day with the Netatmo Smart Weather Station ! Do not miss out on nice weather and sunshine! Access all the information directly on your smartphone and don't miss a single ray of sunshine.

Why measure sunlight levels?

The great importance of the Sun in agrometeorology

Solar radiation, temperature, and water are the main limiting factors of climate on agricultural production. Measuring the duration of sunlight and taking it into account is therefore essential to optimise sowing, harvesting, and all actions related to plants.
The sun is an integral part of the plants' needs for growth. Not all of them have the same need for exposure to sunlight, but the vast majority cannot survive without it.

Sunshine, a determining factor for buying, building, or renting a house

Choosing the right home always involves analysing its brightness and level of sunlight. Nobody wants a dark house or a flat without any sun exposure! It is, therefore, an important criterion in all cases:

  • In construction, this criterion makes it possible to choose the ideal exposure of the house concerning the Sun and to compare plots;
  • Whether you are buying or renting, more sunlight means greater comfort, the possibility of enjoying your exterior and interior more, while saving up money (especially in terms of heating and lighting, with savings of up to €3000 per year)
    A property with an excellent level of sunshine sells well and quickly in the UK. If the local weather is good, even better!

A region with a sunny climate provides a better living environment

Living in the sun has real health and morale benefits. All this depends essentially on the duration and level of sunlight, in other words, on the frequency with which the sun illuminates our days.
In the North of England, the sun rarely shows its face, especially in winter. If you are sensitive to sunshine, it is better to live in a region with a warmer climate and milder weather, such as the south of England. The Old West is not for everyone!

No need for long, complex calculations and endless research to determine the duration of sunlight in your home! The Netatmo Smart Weather Station provides you with all the weather data you need. You can also measure the indoor air quality of your home or the humidity level: the information is at your fingertips (on your smartphone).

3 ways to measure the level of sunlight

The heliograph, the reference device for measuring sunshine

Although it is not widely used by private individuals, the heliograph is the reference instrument for measuring sunshine duration. This sophisticated and precise device is made up of a sensor for the duration of sunshine and direct radiation which estimates this value at a specific point.
The heliograph measures the time when the sun's rays are intense enough to produce distinct shadows: this is the level of sunshine.

Dedicated mobile applications

There are big data solutions for measuring the level of sunlight inside a home. By simulating the trajectory of the Sun over time, you will discover whether a particular flat is well exposed to the sun or, on the contrary, benefits from a low level of sunlight.
The algorithms of some mobile applications make it possible to provide a summary after the data has been compiled. This provides a calculation of the duration and quality of sunlight in a flat or house during the day, but also the year.
Note that these applications use data from national meteorological services.

A connected weather station

These weather stations are effective in measuring all climate and weather-related data: temperature, moon phases, risk of rain, wind… but also sunshine levels. The advantage of this connected object lies in its versatility: you know how much sunshine is expected on Sunday, but also the temperature, wind, and humidity that are expected to accompany it.

The level of sunshine is important for a house as well as for a region: after all, the Sun is vital and makes you happy… so why deprive yourself? Knowing the level of sunshine before settling somewhere means arriving prepared for the climate and weather, but above all for the sun's omnipresence or absence!