There's one more thing to keep in mind about Ohio State. The Buckeyes' only road game so far was at Texas, and they lost it 24-23. That game has been called the largest 4th-quarter collapse by an AP No. 1 team in college football history. Since then Ohio State has won at home by 56 and by 23. A night game in Austin isn't an afternoon at Kinnick, but it's the only time this team has been tested away from home, and it didn't hold up.
Iowa's 4-0 start is real, but it has been close. The Hawkeyes beat Iowa State 16-13. The Michigan win needed a third-down unnecessary roughness penalty at midfield to keep the final drive going. It was their first road win over a ranked Big Ten team since 2015, and the building will know that. Scoring 16 and 20 in their 2 real tests works when the other team can't score either. Ohio State has been able to score on everybody so far.
The early forecast for Iowa City is 64 degrees with a light drizzle, an 18% chance of rain and barely any wind. That's hardly the kind of weather that slows down a passing game, and it's 6 days away, so it can still change. If it turns wet, that favors the team that wants to run the ball and shorten the game, which is exactly Iowa's plan.
Everything depends on whether Iowa can keep this close into the 4th quarter. Brown has already shown he can win it late, and Ohio State has already lost a road game late. If Iowa can't slow down Smith and Sayin early, the fact that the Hawkeyes haven't lost yet won't matter much by halftime.