Mavsum ob-havo, ekologiya va ma'lum bir mintaqadagi kunduzgi soatlarning o'zgarishiga asoslangan yil bo'limi. Yerda fasllar Yerning Quyosh atrofida qiyshaygan orbitasining eksenel parallelligi natijasidir

FASLLAR
Mavsum - ob-havo, ekologiya va ma'lum bir mintaqadagi kunduzgi soatlarning o'zgarishiga asoslangan yil bo'limi. Yerda fasllar Yerning Quyosh atrofida qiyshaygan orbitasining eksenel parallelligi natijasidir. Mo''tadil va qutbli mintaqalarda fasllar Yer yuzasiga tushadigan quyosh nurlari intensivligining o'zgarishi bilan ajralib turadi, ularning o'zgarishi hayvonlarning o'zgarishiga olib kelishi mumkin. qish uyqusi yoki ko'chish, o'simliklar esa uyqu holatida bo'ladi. Turli madaniyatlar fasllar soni va tabiatini mintaqaviy o'zgarishlarga qarab belgilaydilar va shuning uchun fasllar soni o'zgarib turadigan bir qator zamonaviy va tarixiy madaniyatlar mavjud.
Shimoliy yarim sharda eng ko'p to'g'ridan-to'g'ri quyosh nuri may, iyun va iyul oylarida tushadi, chunki yarim shar Quyoshga qaragan. Noyabr, dekabr va yanvar oylarida Janubiy yarim sharda ham xuddi shunday. Aynan Yerning eksenel egilishi, quyoshning yoz oylarida osmonda balandroq bo'lishiga olib keladi, bu esa quyosh oqimini oshiradi. Biroq, mavsumiy kechikishlar tufayli, iyun, iyul va avgust oylari Shimoliy yarim sharda eng issiq oylar, dekabr, yanvar va fevral esa janubiy yarimsharda eng issiq oylardir.


SEASONS
A season is a division of the year based on changes in weather, ecology, and the number of daylight hours in a given region. On Earth, seasons are the result of the axial parallelism of Earth's tilted orbit around the Sun.In temperate and polar regions, the seasons are marked by changes in the intensity of sunlight that reaches the Earth's surface, variations of which may cause animals to undergo hibernation or to migrate, and plants to be dormant. Various cultures define the number and nature of seasons based on regional variations, and as such there are a number of both modern and historical cultures whose number of seasons varies.
The Northern Hemisphere experiences most direct sunlight during May, June, and July, as the hemisphere faces the Sun. The same is true of the Southern Hemisphere in November, December, and January. It is Earth's axial tilt that causes the Sun to be higher in the sky during the summer months, which increases the solar flux. However, due to seasonal lag, June, July, and August are the warmest months in the Northern Hemisphere while December, January, and February are the warmest months in the Southern Hemisphere.