El Nino / La Nina Index (ONI)

The ONI for the April, May, and June 2026 season is +1.0 degrees Celsius, a warm, leaning towards El Nino state. NOAA calls an El Nino event only when the index reaches +0.5 or above for five consecutive seasons, and a La Nina when it reaches -0.5 or below. Source NOAA Climate Prediction Center, compiled and verified by IPOSS, updated monthly.