A Day on Venus Is Longer Than a Year on Venus

Two Very Strange Records

Venus holds two extraordinary records in our solar system. It is the hottest planet (despite not being the closest to the Sun), and it has the longest day of any planet — and that day is longer than its own year.

Venus orbits the Sun in 224.7 Earth days. But it rotates on its axis so slowly that a single Venusian day — from one sunrise to the next — takes 243 Earth days. One Venusian year passes before one Venusian day is complete.

It Also Rotates Backwards

Venus rotates in the opposite direction to most planets in the solar system, including Earth. This is called retrograde rotation. On Venus, the Sun rises in the west and sets in the east. Only Venus and Uranus rotate this way — though Uranus is tilted nearly on its side, which is a different situation.

If you lived on Venus, your birthday would come before your next sunrise.

Why Is Venus So Hot?

Venus's surface temperature averages 465°C (869°F) — hot enough to melt lead. This is not because of its proximity to the Sun (Mercury is closer), but because of a runaway greenhouse effect. Its atmosphere is 96% carbon dioxide with thick clouds of sulphuric acid, trapping heat so effectively that surface temperatures barely vary between day and night, or between the poles and the equator.