The weather in each of the four seasons of the year

Autumn

According to astronomers the autumn equinox is important for autumn. In the days between the 21st and 24th September the day and night last approximately the same amount of time i.e. 12 hours. According to meteorologists, it is the character of the weather, which changes approximately at the beginning of September that is important for the beginning of autumn.

For the weather in autumn these are typical:

• Temperature drop, fog formation (fog is water vapour that is condensed in cooler layers of air above the surface) and hoarfrost (fog sediments on cold objects and natural materials, creating hoarfrost). Pupils measure the temperature by thermometers which must be placed out of the direct sunlight. It is suitable to place a thermometer in a meteorological box. We take the measurements several times a day in regular intervals (due to the possibility of comparing the collected data).

• Increase in airflow, i.e. windy weather. Bigger differences in the temperature of air at night and during the day are caused by more intensive airflow as the warm air rises and cold air replaces it. This creates the continual transfer and circulation of hot and cold air. We measure the direction and the strength of wind by anemometer or by wind vane.

• Higher intensity of precipitations. With the increased airflow, the more intensive movement of cloudiness occurs. The amount of precipitation can be measured by a rain gauge (a container with a calibration).

Winter

The beginning of winter is according to meteorologists on the 1st December, astronomical beginning of winter is between 21st and 23rd December, during the winter equinox. On the day of winter equinox the day is the shortest and the night the longest. The Sun rises the most southerly of true East and sets the most southerly of true West.

For winter weather these are typical:

• Higher cloudiness, precipitations are in the form of snowflakes. Snow protects plants against frost and increases water reserves in the form of snow and ice which are significant for circulation of water in nature.

• Low temperature causes freezing of water areas and watercourses. Ice has a bigger volume and smaller weight than water so that it floats on water. On the bottoms of water areas water never freezes. Water of 4 °C has the biggest density and does not freeze.

Spring

According to meteorologists spring begins on the 1st March, astronomical beginning of spring is between the 20th and 21st March with the Spring Equinox. The day is approximately as long as the night, i.e. 12 hours. Days are gradually getting longer in spring. The Sun rises higher and stays above the horizon longer. Gradually the shadows of objects in nature are getting shorter because the Sun´s rays are perpendicular to the Earth.

For spring weather these are typical:

• Increase of temperature, changeability of weather, and occurrence of light frosts

• Melting of snow and ice causes floods and overflowing river banks.

• In the spring windy weather is more common because the Earth’s surface is warming up unevenly. There are bigger differences between the temperatures at night and in a day. Warm air rises up pushing cold air away, air currents are therefore more intensive. They bring perceptions.

Summer

Begins on the 1st June according to meteorologists, astrological beginning of summer is between the 21st to 22nd June with the Summer solstice. On the day of the Summer solstice the day is the longest and the night the shortest. The sun rises the most southernly of true East and sets the most southernly of true West. Shadows of objects are short at midday because the Sun is the highest on the horizon.

For summer weather these are typical:

• Higher summer temperature

• Frequent thunderstorms – electrical discharges in the atmosphere and accompanied by the sound of thunders.