Meaning
A sun-like circle with longer, bolder rays than its dim partner, the symbol for raising screen brightness. It means bright, more light, turned all the way up.
Apart from settings tips, people use it for sunny days, glowing skin, a bright idea or a sudden burst of energy: “Slept nine hours, feeling 🔆 today” Shops also use it to highlight something new. It contrasts with 🔅 for dim, and ☀️ is the more natural pick for actual weather.