Nature Climate Change, Published online: 25 June 2026; doi:10.1038/s41558-026-02684-zTropical climate, including sea surface temperatures (SSTs), varies with natural cycles such as the El Niño–Southern Oscillation, Indian Ocean Dipole and Atlantic Niño/Niña variability. This work shows that the SST variability weakens under future greenhouse warming, with implications for predictability.