Factual error: Throughout most of the movie almost everyone is wearing dark heavy cloths such as long pants, sweatshirts, etc. They should know better that as hot as it is, they are at GREAT risk of heat stroke or death quicker, than if they dressed more coolly.

Plot hole: If the gasoline in fuel lines and tanks is reaching flash point and exploding, there should not be so many cars just sitting around. Surely all of those vehicles' tanks are not dry.

Factual error: The temperature on earth is increasing more and more throughout the movie. People have been dropping dead left and right, but somehow all plant life is still greener than ever. All the moisture in the ground would be gone by now, so the leaves and grass should be dried up.

Factual error: In the beginning of the film, the camera shows the earth in front of the sun as the asteroid is heading for earth. The side of earth facing the asteroid is lit as if the sun were illuminating it's surface, even though the sun is on the opposite side. It should be dark on this side.