The cloud type that typically marks the top of the troposphere is the cumulonimbus cloud, specifically its flat, anvil-shaped top (called the “anvil”).

Quick Scoop

  • The troposphere is the lowest layer of Earth’s atmosphere, where almost all weather happens.
  • Its upper boundary is the tropopause , which acts like a lid on most vertical air movement.
  • When thunderstorms grow very tall, cumulonimbus clouds rise until they hit this lid, spread out horizontally, and form a broad anvil top.
  • That anvil top of a cumulonimbus is what commonly indicates you’re seeing the top of the troposphere.

In short: when you see a huge thunderstorm cloud with a flat, spreading anvil at the top, you’re looking at a cloud that has grown up to (and often just to) the top of the troposphere.

Information gathered from public forums or data available on the internet and portrayed here.