We offer you to understand what will be the longitude of daylight in different regions of the USA (and beyond the Arctic circle) in January 2021 and why this option may differ significantly for the Central, southern and Northern regions.
Longitude of the day is the period between sunrise and sunset, during which the luminary is above the horizon and illuminates the surface of the Earth.
Geographical location and duration of daylight
What will be the duration of daylight for a particular point of the Earth, influenced by such factors:
- geographical location (Northern hemisphere, southern hemisphere, equator);
- the angle of solar declination (has seasonal changes).
Interesting fact! At the equator the longitude in January and July, and the rest of the year 2021 will be about the same – about 12 hours, but as it approaches the poles of the Earth, this parameter will increasingly deviate from the Equatorial figure.
For the Northern hemisphere, which is USA, day length decreases in winter and increases in summer. Scientists identify the following four key dates in 2021:
The day of the vernal equinox
Daylight is about 12 hours
The summer solstice
The longest day
The day of the autumnal equinox
Daylight is about 12 hours
The winter solstice
The shortest day
Interesting fact! In the southern hemisphere it is diametrically the shortest day of the year falls on June, and the longest in December.
Thus, in latitudes closer to the equator change the duration of the light period of day significantly less than in the North, and far North regions, there is the concept of the polar day (when the longitude of the day is approaching 24 hours) and polar nights (when the parameter is close to 0).
On scientific the longitude of day for a certain point of the globe can be calculated using the formula:
So let’s see what will be the long light of day in certain regions of the USA and how this parameter changes with the latitude.
The length of the day in
Since the winter solstice occurred in the second half of December, the day of the first month of the year is very short, but it gradually increases. The average length of the day in the capital in early January 2021 will be about 7 hours and 10 minutes, and by the last day of the month day of the increase to 8 hours and 30 minutes. Accordingly, the duration of night time reduced from 15 hours and 20 minutes in the beginning of the month up to 14 hours and 10 minutes to 31.01.20.
Based on the data obtained by scientists, we can predict that the capital will be relevant for a schedule:
31 days of January, the height of the solar disk above the horizon also changes from 11.72° at 01.01.20 to 17.04° 31.01.20.
January one of the coldest months for the capital, because in this period, the sun rarely appears from behind the clouds, and at night the temperature can reach extremely low values. These climate indicators are directly linked to the lack of sunlight and are the norm for all settlements located as 55°45′ North latitude.
The length of the day in e
located at 59°57′ North latitude, which causes certain features of daylight in this region.
Interesting fact! Despite the fact that the hallmark of the Northern Capital are the “white nights”, in fact, the region has not seen the polar day and polar night.
In June, the sun disappears behind the horizon, but only for a few hours, and in winter months is shown over the horizon, although the day length is really quite short. In the winter solstice it is 5 hours and 50 minutes. The beginning of a new calendar year day time a little longer, but still will be only 6 hours 2 minutes to 01.01.20 and 7 hours and 50 minutes on the last day of the month.
As you can see, the difference is quite significant when compared with the indicators or the more southern regions of the Russian Federation. Also for Peter will be true for a schedule change of light and dark periods of day: