Category: Extremes affecting Tonga

Heat wave occuring from August 20 2025 to September 11 2025 at -13.0°S 192.5°E

Download data: JSON

Event type: Heat wave

Countries affected (identified with ArcGIS Online; provided only for geographical reference):

  • Australia
  • Fiji
  • New Zealand
  • Tonga

Duration: 23 days

Time span: August 20 2025 to September 11 2025

Statistics over entire affected area:

  • Mean temperature anomaly: 1.7 °C
  • Mean temperature: 20.5 °C
  • Maximum temperature anomaly: 3.6 °C
  • Maximum temperature: 28.0 °C

Event center: -13.0°S 192.5°E

Area affected: 6868306 km$^2$


Fig. 1: Map of most extreme temperature anomalies (standardized) experienced during the event. The purple star indicates the center of the extreme event. Green hatching illustrates all areas under the effect of extremes at some time during the event.



Fig. 2: Evolution of temperature at the center of the event. The climatological percentile distribution is illustrated with color shadings.



Fig. 3: Maps illustrating the evolution of standardized temperature anomalies during the event.

Event ID: Heat_wave_2025-Aug-20_to_2025-Sep-11_192.5_-13.0

Heat wave occuring from March 18 2025 to March 31 2025 at -19.5°S 185.5°E

Download data: JSON

Event type: Heat wave

Countries affected (identified with ArcGIS Online; provided only for geographical reference):

  • Tonga

Duration: 14 days

Time span: March 18 2025 to March 31 2025

Statistics over entire affected area:

  • Mean temperature anomaly: 1.1 °C
  • Mean temperature: 27.2 °C
  • Maximum temperature anomaly: 1.9 °C
  • Maximum temperature: 28.4 °C

Event center: -19.5°S 185.5°E

Area affected: 303387 km$^2$


Fig. 1: Map of most extreme temperature anomalies (standardized) experienced during the event. The purple star indicates the center of the extreme event. Green hatching illustrates all areas under the effect of extremes at some time during the event.



Fig. 2: Evolution of temperature at the center of the event. The climatological percentile distribution is illustrated with color shadings.



Fig. 3: Maps illustrating the evolution of standardized temperature anomalies during the event.

Event ID: Heat_wave_2025-Mar-18_to_2025-Mar-31_185.5_-19.5

Cold spell occuring from January 11 2025 to January 15 2025 at -22.0°S 184.0°E

Download data: JSON

Event type: Cold spell

Countries affected (identified with ArcGIS Online; provided only for geographical reference):

  • Tonga

Duration: 5 days

Time span: January 11 2025 to January 15 2025

Statistics over entire affected area:

  • Mean temperature anomaly: -1.7 °C
  • Mean temperature: 23.3 °C
  • Minimum temperature anomaly: -2.4 °C
  • Minimum temperature: 22.0 °C

Event center: -22.0°S 184.0°E

Area affected: 68277 km$^2$


Fig. 1: Map of most extreme temperature anomalies (standardized) experienced during the event. The purple star indicates the center of the extreme event. Green hatching illustrates all areas under the effect of extremes at some time during the event.



Fig. 2: Evolution of temperature at the center of the event. The climatological percentile distribution is illustrated with color shadings.



Fig. 3: Maps illustrating the evolution of standardized temperature anomalies during the event.

Event ID: Cold_spell_2025-Jan-11_to_2025-Jan-15_184.0_-22.0

Cold spell occuring from August 08 2024 to August 16 2024 at -17.5°S 195.5°E

Download data: JSON

Event type: Cold spell

Countries affected (identified with ArcGIS Online; provided only for geographical reference):

  • Samoa
  • Tonga

Duration: 9 days

Time span: August 08 2024 to August 16 2024

Statistics over entire affected area:

  • Mean temperature anomaly: -1.5 °C
  • Mean temperature: 23.3 °C
  • Minimum temperature anomaly: -2.6 °C
  • Minimum temperature: 19.8 °C

Event center: -17.5°S 195.5°E

Area affected: 1491852 km$^2$


Fig. 1: Map of most extreme temperature anomalies (standardized) experienced during the event. The purple star indicates the center of the extreme event. Green hatching illustrates all areas under the effect of extremes at some time during the event.



Fig. 2: Evolution of temperature at the center of the event. The climatological percentile distribution is illustrated with color shadings.



Fig. 3: Maps illustrating the evolution of standardized temperature anomalies during the event.

Event ID: Cold_spell_2024-Aug-08_to_2024-Aug-16_195.5_-17.5

Cold spell occuring from October 05 2023 to October 07 2023 at -19.5°S 187.0°E

Download data: JSON

Event type: Cold spell

Countries affected (identified with ArcGIS Online; provided only for geographical reference):

  • Tonga

Duration: 3 days

Time span: October 05 2023 to October 07 2023

Statistics over entire affected area:

  • Mean temperature anomaly: -1.9 °C
  • Mean temperature: 21.9 °C
  • Minimum temperature anomaly: -2.9 °C
  • Minimum temperature: 19.8 °C

Event center: -19.5°S 187.0°E

Area affected: 139938 km$^2$


Fig. 1: Map of most extreme temperature anomalies (standardized) experienced during the event. The purple star indicates the center of the extreme event. Green hatching illustrates all areas under the effect of extremes at some time during the event.



Fig. 2: Evolution of temperature at the center of the event. The climatological percentile distribution is illustrated with color shadings.



Fig. 3: Maps illustrating the evolution of standardized temperature anomalies during the event.

Event ID: Cold_spell_2023-Oct-05_to_2023-Oct-07_187.0_-19.5

Cold spell occuring from June 12 2023 to June 16 2023 at -19.5°S 188.0°E

Download data: JSON

Event type: Cold spell

Countries affected (identified with ArcGIS Online; provided only for geographical reference):

  • Tonga

Duration: 5 days

Time span: June 12 2023 to June 16 2023

Statistics over entire affected area:

  • Mean temperature anomaly: -1.7 °C
  • Mean temperature: 23.0 °C
  • Minimum temperature anomaly: -3.1 °C
  • Minimum temperature: 20.6 °C

Event center: -19.5°S 188.0°E

Area affected: 230887 km$^2$


Fig. 1: Map of most extreme temperature anomalies (standardized) experienced during the event. The purple star indicates the center of the extreme event. Green hatching illustrates all areas under the effect of extremes at some time during the event.



Fig. 2: Evolution of temperature at the center of the event. The climatological percentile distribution is illustrated with color shadings.



Fig. 3: Maps illustrating the evolution of standardized temperature anomalies during the event.

Event ID: Cold_spell_2023-Jun-12_to_2023-Jun-16_188.0_-19.5

Heat wave occuring from May 27 2023 to June 02 2023 at -14.5°S 178.5°E

Download data: JSON

Event type: Heat wave

Countries affected (identified with ArcGIS Online; provided only for geographical reference):

  • Fiji
  • Tonga

Duration: 7 days

Time span: May 27 2023 to June 02 2023

Statistics over entire affected area:

  • Mean temperature anomaly: 1.8 °C
  • Mean temperature: 25.2 °C
  • Maximum temperature anomaly: 3.1 °C
  • Maximum temperature: 28.3 °C

Event center: -14.5°S 178.5°E

Area affected: 1107534 km$^2$


Fig. 1: Map of most extreme temperature anomalies (standardized) experienced during the event. The purple star indicates the center of the extreme event. Green hatching illustrates all areas under the effect of extremes at some time during the event.



Fig. 2: Evolution of temperature at the center of the event. The climatological percentile distribution is illustrated with color shadings.



Fig. 3: Maps illustrating the evolution of standardized temperature anomalies during the event.

Event ID: Heat_wave_2023-May-27_to_2023-Jun-02_178.5_-14.5

Heat wave occuring from December 28 2022 to February 11 2023 at -22.0°S 174.5°E

Download data: JSON

Event type: Heat wave

Countries affected (identified with ArcGIS Online; provided only for geographical reference):

  • Australia
  • Fiji
  • New Caledonia
  • New Zealand
  • Norfolk Island
  • Papua New Guinea
  • Solomon Islands
  • Tonga
  • Vanuatu

Duration: 46 days

Time span: December 28 2022 to February 11 2023

Statistics over entire affected area:

  • Mean temperature anomaly: 2.1 °C
  • Mean temperature: 21.6 °C
  • Maximum temperature anomaly: 11.2 °C
  • Maximum temperature: 29.4 °C

Event center: -22.0°S 174.5°E

Area affected: 15248407 km$^2$


Fig. 1: Map of most extreme temperature anomalies (standardized) experienced during the event. The purple star indicates the center of the extreme event. Green hatching illustrates all areas under the effect of extremes at some time during the event.



Fig. 2: Evolution of temperature at the center of the event. The climatological percentile distribution is illustrated with color shadings.



Fig. 3: Maps illustrating the evolution of standardized temperature anomalies during the event.

Event ID: Heat_wave_2022-Dec-28_to_2023-Feb-11_174.5_-22.0

Heat wave occuring from October 11 2022 to November 06 2022 at -25.5°S 196.5°E

Download data: JSON

Event type: Heat wave

Countries affected (identified with ArcGIS Online; provided only for geographical reference):

  • Tonga

Duration: 27 days

Time span: October 11 2022 to November 06 2022

Statistics over entire affected area:

  • Mean temperature anomaly: 2.2 °C
  • Mean temperature: 17.9 °C
  • Maximum temperature anomaly: 4.0 °C
  • Maximum temperature: 26.7 °C

Event center: -25.5°S 196.5°E

Area affected: 9008122 km$^2$


Fig. 1: Map of most extreme temperature anomalies (standardized) experienced during the event. The purple star indicates the center of the extreme event. Green hatching illustrates all areas under the effect of extremes at some time during the event.



Fig. 2: Evolution of temperature at the center of the event. The climatological percentile distribution is illustrated with color shadings.



Fig. 3: Maps illustrating the evolution of standardized temperature anomalies during the event.

Event ID: Heat_wave_2022-Oct-11_to_2022-Nov-06_196.5_-25.5

Heat wave occuring from June 01 2022 to June 05 2022 at -18.5°S 186.0°E

Download data: JSON

Event type: Heat wave

Countries affected (identified with ArcGIS Online; provided only for geographical reference):

  • Tonga

Duration: 5 days

Time span: June 01 2022 to June 05 2022

Statistics over entire affected area:

  • Mean temperature anomaly: 1.6 °C
  • Mean temperature: 26.1 °C
  • Maximum temperature anomaly: 2.1 °C
  • Maximum temperature: 27.0 °C

Event center: -18.5°S 186.0°E

Area affected: 113501 km$^2$


Fig. 1: Map of most extreme temperature anomalies (standardized) experienced during the event. The purple star indicates the center of the extreme event. Green hatching illustrates all areas under the effect of extremes at some time during the event.



Fig. 2: Evolution of temperature at the center of the event. The climatological percentile distribution is illustrated with color shadings.



Fig. 3: Maps illustrating the evolution of standardized temperature anomalies during the event.

Event ID: Heat_wave_2022-Jun-01_to_2022-Jun-05_186.0_-18.5