Climate Patterns
Madden-Julian Oscillation Explained: Tropical Waves That Influence Weather
What the MJO is, how it moves through the tropics, and why it can influence storms, rainfall, tropical cyclones, and winter patterns.
Quick answer: The Madden-Julian Oscillation is a moving pulse of tropical rainfall and thunderstorm activity that can influence weather patterns around the world.
What moves
The MJO is not a single storm. It is a broad area of enhanced and suppressed tropical convection that moves eastward over time.
Its phase and strength can affect where tropical rainfall is favored.
Why forecasters care
The MJO can influence tropical cyclone development, monsoon rainfall, jet stream patterns, and sometimes winter storm setups.
Its effects vary by season and background climate pattern.
How to use it
For everyday users, the MJO is background context rather than a direct forecast.
It helps explain why some multi-week weather patterns become more favorable for storms or quiet periods.