The average annual temperature on Mars is -64°F. At its hottest, Mars could hit 80°F near the equator in the middle of the day. In the Martian winter, however, temperatures could fall to -199°F.

That's why the first requirement for visiting the Red Planet would be a space suit.

But we were curious: How long could someone survive a summer day on Mars without all this fancy equipment, say, wearing only jeans and T-shirt and while holding his or her breath — which the average human can only do for a little more than a minute.