What is the difference between summer and heat?

Weather of Arabia - Dr. Khaled Al-Zaaq, a member of the Arab Union for Astronomy and Space Sciences, confirmed that the most important stars for calculating heat are “Pleiades and Gemini.”
“Al-Zaaq” explained in a tweet on his Twitter account that “the disappearance of the Pleiades is called the sunrise of the Pleiades (summer), the disappearance of Gemini is called the sky of Gemini (heat), and the appearance of the Pleiades from the east with the sun is called the square of the heat.”
In a video clip from his calendar program on Al-Arabiya channel, Al-Zaaq explained, saying:

"The Arabs have a hot summer. Summer is considered the beginning of heat, and hot is the intensity of heat. Summer begins with the appearance of the Pleiades before sunrise from the eastern side, while hot weather begins with the absence of Gemini with the absence of the sun from the western side."
He added: “The absence of Gemini with the absence of the sun is called (Gemini’s palm), and this is the situation we are in now, and it will continue for 40 days, after which Gemini will appear and her reckoning will begin. The ancients said (If Gemini rises, fill the chamber), as Gemini is considered the palm of the hand. Gemini is considered one of the guiding stars.”