Scope ii

Foreword iii

Acknowledgements iv

List of abbreviations vii

Executive summary viii

Introduction 1

  Data sources 3

  Anomaly calculation 4

Semi-decadal statement 6

  Report background and developments 7

  Semi-decadal status 8

  Perspective 11

Overview of climatic conditions in 2025 13

  Precipitation 14

  Extreme precipitation 16

River discharge 17

Reservoirs 22

  Inflow into selected reservoirs 22

  Reservoir storage 23

Lakes 25

  Lake levels 26

  Lake water temperature 27

  Ice cover duration 28

Groundwater levels 29

Soil moisture 32

Evapotranspiration 35

Terrestrial water storage 37

Snow cover and glaciers 39

  Snow water equivalent and peak snow mass 39

  Glaciers 41

Water quality 44

  Observed water quality 44

  Observed water temperature 44

  Modelled river temperature 46

High-impact hydrological events 48

  Floods in the Democratic Republic of the Congo 50

  Drought in the Greater Horn of Africa 50

  Floods in Nigeria 50

  Floods in southern Africa 50

  Floods in Pakistan 51

  Floods in Sri Lanka 51

  Floods in Indonesia, Thailand and Malaysia 51

  Floods in Viet Nam 51

  Floods in the Philippines 51

  Drought in Armenia, Türkiye, the Islamic Republic of Iran, the Syrian Arab Republic and Jordan 51

  Floods in Jamaica, Cuba, Haiti and the Dominican Republic 52

  Floods in northern Australia 52

  Floods in the United States 52

  Drought in Argentina and Chile 53

  Drought in Europe 53

  Floods in France 53

Outlook 54

References 56

Annex. Technical annex 61