Turns out it’s anything but arbitrary.
Despite what you may have heard, that number is far from arbitrary. In fact, 350 degrees marks the magical point at which food goes from dull to delicious. Well-versed chefs know this as the Maillard reaction, which Tasting Table describes as “the phenomenon responsible for browning protein and sugars.” Reaching this point creates a new set of complex flavors, and it only occurs between 300 and 350 degrees, A.K.A. the culinary promised land. Lower temperatures can result in bland, pale goodies, and nobody wants that.
Now, that doesn’t mean everything should be cooked at 350 degrees. On the contrary, that temperature can do more harm than good to foods like chicken and pie crusts. But the next time you find yourself winging it in the kitchen, 350 degrees will rarely let you down.