Crews spent Monday laying down the new field for Super Bowl 50, which will be played next month at Levi's Stadium in Santa Clara.
NFL Field Director Ed Mangan said he checks the weather forecast at least once an hour.
"We'll deal with mother natures as she comes," Mangan said. "If it's going to rain, it's going to rain. We'll prepare for it."
Mangan admits light-to-moderate rain is welcome.
But what if El Niño storms bring massive downpours on the freshly-laid grass?
"If that's an inch in a half an hour, we've got a problem," Mangan said.
Mangan said rain and cold weather tarps will be used to protect the field if need be.
On Monday, 75,000 square feet of fresh grass was laid on the field like a puzzle.
For 86-year-old George Toma, a self-proclaimed "nitty gritty dirt man," Super Bowl 50 will also mark his 50th anniversary with the National Football League.
Toma has been in the football field business since he was a kid.
While football fans hope for a good game on Super Bowl Sunday, Mangan is focused on a strong field.
"It is a natural grass field, so weather is going to change the playability of the field," Mangan said.