A quiz host asks what causes the seasons, and a contestant answers that Earth is closer to the Sun in summer. NASA’s Space Place says many people believe that, and that the idea, although it makes sense, is incorrect. This guide takes the common traps one at a time from three bodies: NASA Space Place (article last updated 29 July 2025), two NOAA NESDIS education pages (one with a publication date of 26 August 2025, one undated) and six undated Met Office pages, which give dates for the Northern Hemisphere and the UK.
Trap One: Summer Means Closest to the Sun
NASA Space Place says Earth’s tilted axis causes the seasons, and NESDIS says Earth has seasons because its axis is tilted. Both pages say the orbit is not a perfect circle, so Earth is closer to the Sun during part of the year, but that in the Northern Hemisphere it is winter when Earth is closest and summer when it is farthest away. Both give the same distances: perihelion, the closest point, is 91,400,000 miles and aphelion, the farthest, is 94,500,000 miles. A gap of over 3 million miles, they say, is not much relative to the entire distance.
The month detail makes a good quiz answer. Both pages say aphelion occurs in July and perihelion in January, and both conclude that Earth’s distance from the Sun is not the cause of the seasons.
What the Tilt Does
NASA Space Place says that as Earth orbits the Sun its tilted axis always points in the same direction, so different parts of Earth get the Sun’s direct rays through the year. It says the North Pole tilts toward the Sun around June and the South Pole around December, which is why it is summer in June in the Northern Hemisphere. The tilt figure differs slightly by page: the Met Office gives 23.5 degrees, one NESDIS page 23.5 degrees and the other NESDIS page 23.45 degrees measured from the perpendicular.
Trap Two: Equal Day and Night on the Equinox
The pages word this differently. NESDIS says the equinoxes, in March and September, mark when the Sun is exactly above the Equator and that this makes day and night equal length. The Met Office’s spring page says the vernal equinox marks a balance of 12 hours of day and night. The Met Office’s equinox page says the Sun crosses the equator on these days, resulting in nearly equal lengths of day and night, and that the equilux is the precise day when they are exactly equal. It places the equilux a few days before the spring equinox and a few days after the autumn equinox, and attributes the difference to the Sun’s apparent size and atmospheric refraction.
Trap Three: The Shortest Day Has the Earliest Sunset
The Met Office says the winter solstice, around 21 December in the Northern Hemisphere, is the shortest day, with the Sun at its lowest midday position. Its winter page then adds that the earliest sunset occurs a few days before the solstice, due to the way clocks align with the Earth’s orbit. A question that asks for the earliest sunset therefore does not have the solstice as its answer, on the Met Office’s account.
Trap Four: One Start Date for Each Season
The Met Office gives two definitions for each UK season. Its meteorological seasons are fixed three-month blocks, which it says makes weather statistics easier to compare; its astronomical seasons follow the equinoxes and solstices.
| Season | Meteorological | Astronomical |
|---|---|---|
| Spring | 1 March to 31 May | Starts at the vernal equinox, around 20 March |
| Summer | 1 June to 31 August | Starts around 21 June, the summer solstice; ends around 22 September |
| Autumn | 1 September to 30 November | Starts at the autumn equinox, usually around 22 or 23 September |
| Winter | 1 December to the last day of February | Starts at the winter solstice, usually around 21 December; ends around 20 March |
The astronomical dates are worded with “around” and “usually”: the equinox page puts the autumn equinox around 22 September, the autumn page says usually around 22 or 23 September, and that page adds that exact dates can vary slightly each year.
Trap Five: Every Place Has the Same Season at Once
NASA Space Place says the poles are at opposite ends of Earth and so experience opposite timing for the seasons. NESDIS puts it as: when the North Pole is tilted toward the Sun it is summer in the Northern Hemisphere and winter in the Southern, and when the South Pole is tilted toward the Sun the reverse holds. The Met Office says that at the summer solstice regions north of the Arctic Circle have 24 hours of daylight while areas south of the Antarctic Circle are in complete darkness, and that this pattern reverses at the winter solstice.
Quick Answers for the Quiz Table
- Cause of the seasons: Earth’s axial tilt (NASA Space Place, NESDIS and the Met Office).
- Month of perihelion and aphelion: January and July (NASA Space Place and NESDIS).
- Shortest day in the Northern Hemisphere: the winter solstice, around 21 December (Met Office).
- Meteorological autumn in the UK: 1 September to 30 November (Met Office).
- Exactly equal day and night: the equilux, not the equinox itself, on the Met Office’s account.
The bottom line
NASA Space Place, NESDIS and the Met Office each put the seasons down to Earth’s axial tilt, and NASA Space Place and NESDIS add that Earth is closest to the Sun in January and farthest in July, so distance is not the cause. The pages differ on the wording for equinoxes, from equal to nearly equal, and the Met Office gives dates for the Northern Hemisphere and the UK with two ways of dating a season, the fixed calendar months or the astronomical dates, which it says can vary slightly each year.
Sources
- What Causes the Seasons?, NASA Space Place (spaceplace.nasa.gov), article last updated 29 July 2025, read 12 November 2026
- Why does Earth have Seasons?, NESDIS, NOAA (nesdis.noaa.gov), publication date 26 August 2025, read 12 November 2026
- Changing of the Seasons, NESDIS, NOAA (nesdis.noaa.gov), page undated, read 12 November 2026
- The four seasons; Understanding equinoxes and solstices; Spring; Summer; Autumn; Winter, Met Office (weather.metoffice.gov.uk), pages undated, read 12 November 2026
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