El Niño-Southern Oscillation (ENSO) wani yanayi ne na yanayin da ke faruwa a cikin tekun Pacific na wurare masu zafi. Yana da yanayin ɗumamar sararin teku a tsakiyar tsakiyar da gabashin equatorial Pacific, wanda yawanci yakan faru a cikin 'yan shekaru, kuma yana iya haifar da gagarumin canje-canje a yanayin yanayi na duniya.El Niño yana nufin yanayin zafi na duniya. ENSO, lokacin da yanayin saman teku a tsakiya da gabashin Pacific ya fi zafi fiye da na al'ada. Hakan na iya haifar da karuwar ruwan sama da ambaliya a wasu yankuna, da fari a wasu yankuna.La Niña kuwa, tana nufin yanayin sanyi na ENSO, wanda a lokacin yanayin zafi a saman teku a tsakiya da gabas. Pacific suna da sanyi fiye da na al'ada. Wannan na iya haifar da sabanin yanayin yanayi, gami da fari a wasu wurare da kuma karuwar ruwan sama a wasu. Lokacin da aka haɗa tare da sauye-sauyen teku, wannan zai iya haifar da tasirin yanayi na El Niño da La Niña.