Potential Questions or Issues
Students will likely be confused when they discover that the Earth is closest to the Sun (Perihelion) in January of each year; it is not hotter in the northern hemisphere in January. Teachers should assure the students that the Earth is not significantly closer to the Sun, and that the position of the continents and the oceans has a stronger effect on the seasons than the proximity of Earth to the Sun.
Students may be concerned by the seasonal lag--that the temperatures are hotter in July and August in the northern hemisphere instead of June, even though the northern hemisphere receives the most sunlight in June. Teachers can address this with activities measuring how long it takes various surfaces to heat up or cool off.
Some planets, such as Mars, have more elliptical orbits, and their proximity to the Sun does influence their seasons more strongly than Earth experiences.