-109.3° F. Dry ice is simply frozen carbon dioxide, and changes from a solid to a gas directly, without becoming a liquid first. For this reason it is often used in refrigerated packing materials as there is no damaging liquid to contend with as it melts.
But if you wanted to freeze something, you would do better to use liquid nitrogen (-196° F), which is colder and the liquid state allows you to dip things into it and thereby achieve a frozen state almost instantly. When things are frozen in this manner you can do things such as throw them on the ground and watch them shatter as if they were made of glass. A flower. A rubber ball. A balloon. If you touched liquid nitrogen directly, or put your finger in it, you would get a severe burn. People who work with liquid nitrogen use goggles and heavy cold-proof gloves. Sometimes doctors use a tiny amount to remove a wart on your skin. They use it to “cold burn” your skin and then the blister heals and falls off, taking the dead wart with it.