Leo is a Summer Zodiac Sign (as are the Signs of Cancer and Virgo). This time of the year is also known as the Summer Solstice when the days are longer and the nights are shorter than at any other time during the year.
In the Northern Hemisphere, Summer usually begins on June 21, while in the Southern Hemisphere, it begins around December 21. However, for the purposes of Astrology, the Northern Hemisphere time frame marks the beginning of this Season.
Summer influence on Leo personalities
In general, individuals who fall under the jurisdiction of Summer have more measured responses than those governed by Spring and, though equally as enthusiastic, tend to be more critical. The energies here are perhaps less focused on the initiation of projects and geared more toward bringing those projects to fruition.