Why do some winters bring much more rain than others in the same region?

Rainfall can change from year to year because the atmosphere and oceans are linked in large-scale patterns. During El Niño, the central and eastern tropical Pacific become warmer than average, altering jet streams and storm tracks around the world. La Niña tends to produce the opposite pattern, often shifting rainfall and drought risk in different regions. Local geography matters too, but ocean-atmosphere cycles are a major driver of wet and dry winters across many continents.