Understanding The Four Seasons

Understanding The Four Seasons

Posted on 01 Dec 2023

“Spring is the time of year when it is summer in the sun and winter in the shade.” - Charles Dickens, Great Expectations.

As we approach the winter solstice, a time of year surrounded in myths and legends, many people around the world start to prepare for a unique time where the sun appears to stand still. The very word ‘solstice’ means just that, the moment the sun stands still, and changes its apparent journey.

The megalithic Neolithic henges of Stonehenge and Avebury in the UK are among the most iconic and widely-recognised prehistoric monuments in the world, and are now classified as Unesco world heritage sites. Their importance to the ancient world is even today not fully understood, however their mere existence demonstrates the detailed knowledge of the skies possessed by ancient civilizations. 

It is known that the circles were used by communities to celebrate the key points of the movement of the sun, being constructed by farmers, who understood the importance of the sky, sun and weather for their survival.

Fast-forward to 1984, where over 30,000 people gathered at the site at the summer solstice, prompting the restrictions that exist today to protect the area, and preserve the delicate archaeology that is still being discovered. 

There is no doubt that the sun, sky, seasons and weather are as emotive to modern people as to our ancestors, and the passing of the seasons, and the changing weather has a seemingly inbuilt interest within our psyche.

Astronomical and Meteorological Seasons

Astronomers and meteorologists take a different approach to defining when the four seasons start and finish.

The astronomer's view is based on the position of the Earth in relation to the Sun. More specifically, the start of each season is marked by either a solstice (for winter and summer) or an equinox (for spring and autumn). A solstice is when the sun reaches the most southerly or northerly point in the sky, while an equinox is when the sun passes over Earth’s equator. Because of leap years, the dates of the equinoxes and solstices can shift by a day or two over time, causing the start dates of the seasons to shift.

In contrast, the meteorologist's start of a season is based on the annual temperature cycle and the 12-month calendar. According to this definition, each season begins on the first of a particular month and lasts for three months: Spring begins on 1st March, summer on 1st June, autumn on 1st September, and winter on 1st December. Climate scientists and meteorologists created this definition to make it easier to keep records of the weather, since the start of each meteorological season doesn’t change from year to year.

The OpenWeather One Call API 3.0 has been updated to give an unprecedented 1.5 year forecast of daily aggregated weather data, as well as a four-day forecast data for any given timestamp (in addition to 40+ years of historic timestamp data). This data can be utilized by a wide variety of industries and individuals. 

For example, Insurance organizations can use this data to assess the risks for certain tourist destinations during particular seasons. They can also use this information to warn their customers of potential historical weather related dangers that they may encounter.


Due to the lack of sunlight, days may appear to be shorter during the winter months, in ancient Rome they actually were. Using a system inherited from the ancient Egyptians, an hour was allotted 75 minutes in the summer, but only 45 minutes in the winter.

The winter solstice is the “shortest day of the year”, meaning the least amount of sunlight. The Sun reaches its most southern point in the sky (in the Northern Hemisphere) at noon. After this date, the days start getting “longer,” in other words the amount of daylight begins to increase. Perhaps counter intuitively, the sun is actually closer to the earth than at any other time, it is the all important global tilt of the earth relative to the sun that causes the number of sunlight hours to be at their minimum. 

Constant darkness and freezing weather conditions engulf Iceland (known as the ‘Land of Fire and Ice’), however due to geothermal technology developed over the past 20 years, this unique environment can produce organic and tasty crops such as ripe red tomatoes and crisp fresh cucumbers. The technology uses geothermal energy to heat underground reserves of hot water and steam that is used to produce electricity, melt snow from streets, heat homes and offices and greenhouses. 


Astronomically speaking, the first day of spring is marked by the spring equinox, which falls on the 19th, 20th or 21st March each year for the northern hemisphere (or autumn in the Southern hemisphere). The equinox happens at the same moment worldwide, although our clock times reflect a different time zone. 

For the farming community, springtime is when it becomes possible to move cattle from their indoor winter protection to the fields, often leaping with joy! Arable farmers see their crops start to grow, and apply fertilizers as well as cutting the newly grown grass for hay. 

Understanding when these tasks need to be done requires an understanding of the weather conditions. The OpenWeather Daily Forecast 16 Days API gives daily weather forecast information for anywhere in the world, and can be used to plan equipment hire and manage staff and critical times of the farming year.


This season brings sun-seekers to beaches and tourists to the airports. For example, 2022 brought record breaking temperatures around the world, with the UK’s first recorded 40C. 

In the UK, Water companies must legally prepare a drought plan every five years. The plan must state how they will maintain a secure water supply and protect the environment during dry weather and drought. Part of the plan is to describe certain points, known as triggers, at which they will take certain mitigating action. 

Examples of triggers might be:

  • rainfall levels

  • river flows

  • groundwater levels

  • reservoir stocks

The OpenWeather Global Precipitation Maps gives current, forecast and historical global precipitation weather maps with a 10 minutes-step via the easy-to-work API. This enables water companies to manage their water supply, and be given prior warning of heavy rainfall that might cause summer floods at times when the ground is dry.


The time when the leaves turn golden brown and the summer heat starts to subside and crops are harvested. One of the most iconic, and important agricultural machines is the Combine Harvester. The initial idea came from the Scottish inventor Reverend Patrick Bell, who in 1826 designed a horse-drawn machine with large scissors to harvest the crops. Later, in 1835, in the United States, Hiram Moore built and patented the first combine harvester, which was capable of reaping, threshing and winnowing cereal grain. Today, the largest "class 11" combines are fitted with headers up to 18m wide, and are as powerful as a formula 1 car. 

Farmers need to have accurate, short-term weather forecasts to be able to plan the all important harvesting. The OpenWeather Hourly forecast API gives finely grained, accurate hourly forecasts for four days, perfect for managing this critical part of the farming year’s activities.  

Charles Dickens understood that the seasons had their own character, could merge at times, and vary year to year. The OpenWeather library of products give a clear, accessible, accurate and detailed insight into the weather, and help us all understand the nuances of our global weather.

About OpenWeather:

OpenWeather provides weather data for any location on the globe using a proprietary hyperlocal forecasting model with a resolution from 500 m to 2 km, globally. More than 5,000,000 customers from logistics, agriculture, insurance, energy, retail, and many other sectors, are working with the company's weather products. 

OpenWeather cooperates with global meteorological agencies such as MetOffice and NOAA, and enhances its model with data from radars, weather stations and satellites. The company provides great availability of service at 99.9% for enterprise-level products. 

The products can be easily integrated into complex IT systems and are ideal for ML analytic systems. OpenWeather is a member of Royal Meteorological Society and an Achilles-certified supplier. OpenWeather ethical initiatives include support of educators and students, not-for-profit subscriptions for the general public to increase weather awareness, and the recent Ukrainian donation programme.

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