Category: Weather Extremes – all events

Heat wave occuring from September 10 2025 to September 12 2025 at 43.0°N 112.0°E

Download data: JSON

Event type: Heat wave

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

  • China
  • Mongolia

Duration: 3 days

Time span: September 10 2025 to September 12 2025

Statistics over entire affected area:

  • Mean temperature anomaly: 5.7 °C
  • Mean temperature: 21.9 °C
  • Maximum temperature anomaly: 7.2 °C
  • Maximum temperature: 24.1 °C

Event center: 43.0°N 112.0°E

Area affected: 68109 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-Sep-10_to_2025-Sep-12_112.0_43.0

Heat wave occuring from September 10 2025 to September 15 2025 at 89.0°N 174.0°E

Download data: JSON

Event type: Heat wave

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

  • Canada

Duration: 6 days

Time span: September 10 2025 to September 15 2025

Statistics over entire affected area:

  • Mean temperature anomaly: 3.4 °C
  • Mean temperature: -1.7 °C
  • Maximum temperature anomaly: 4.3 °C
  • Maximum temperature: -0.8 °C

Event center: 89.0°N 174.0°E

Area affected: 105162 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-Sep-10_to_2025-Sep-15_174.0_89.0

Cold spell occuring from September 10 2025 to September 15 2025 at -18.5°S 133.0°E

Download data: JSON

Event type: Cold spell

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

  • Australia

Duration: 6 days

Time span: September 10 2025 to September 15 2025

Statistics over entire affected area:

  • Mean temperature anomaly: -5.7 °C
  • Mean temperature: 17.8 °C
  • Minimum temperature anomaly: -10.9 °C
  • Minimum temperature: 11.8 °C

Event center: -18.5°S 133.0°E

Area affected: 873596 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-Sep-10_to_2025-Sep-15_133.0_-18.5

Heat wave occuring from September 09 2025 to September 12 2025 at -70.5°S 9.0°E

Download data: JSON

Event type: Heat wave

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

  • Antarctica

Duration: 4 days

Time span: September 09 2025 to September 12 2025

Statistics over entire affected area:

  • Mean temperature anomaly: 8.1 °C
  • Mean temperature: -13.4 °C
  • Maximum temperature anomaly: 10.7 °C
  • Maximum temperature: -10.7 °C

Event center: -70.5°S 9.0°E

Area affected: 55971 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-Sep-09_to_2025-Sep-12_9.0_-70.5

Cold spell occuring from September 09 2025 to September 12 2025 at -23.0°S 126.0°E

Download data: JSON

Event type: Cold spell

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

  • Australia

Duration: 4 days

Time span: September 09 2025 to September 12 2025

Statistics over entire affected area:

  • Mean temperature anomaly: -4.9 °C
  • Mean temperature: 18.2 °C
  • Minimum temperature anomaly: -6.0 °C
  • Minimum temperature: 15.6 °C

Event center: -23.0°S 126.0°E

Area affected: 145039 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-Sep-09_to_2025-Sep-12_126.0_-23.0

Cold spell occuring from September 09 2025 to September 12 2025 at 23.5°N 32.0°E

Download data: JSON

Event type: Cold spell

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

  • Egypt
  • Sudan

Duration: 4 days

Time span: September 09 2025 to September 12 2025

Statistics over entire affected area:

  • Mean temperature anomaly: -2.7 °C
  • Mean temperature: 29.6 °C
  • Minimum temperature anomaly: -3.8 °C
  • Minimum temperature: 26.5 °C

Event center: 23.5°N 32.0°E

Area affected: 96386 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-Sep-09_to_2025-Sep-12_32.0_23.5

Heat wave occuring from September 09 2025 to September 13 2025 at 68.5°N 243.5°E

Download data: JSON

Event type: Heat wave

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

  • Canada

Duration: 5 days

Time span: September 09 2025 to September 13 2025

Statistics over entire affected area:

  • Mean temperature anomaly: 6.4 °C
  • Mean temperature: 9.1 °C
  • Maximum temperature anomaly: 9.7 °C
  • Maximum temperature: 12.8 °C

Event center: 68.5°N 243.5°E

Area affected: 79542 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-Sep-09_to_2025-Sep-13_243.5_68.5

Heat wave occuring from September 09 2025 to September 13 2025 at 0.5°N 124.5°E

Download data: JSON

Event type: Heat wave

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

  • Indonesia

Duration: 5 days

Time span: September 09 2025 to September 13 2025

Statistics over entire affected area:

  • Mean temperature anomaly: 1.0 °C
  • Mean temperature: 26.9 °C
  • Maximum temperature anomaly: 1.7 °C
  • Maximum temperature: 27.8 °C

Event center: 0.5°N 124.5°E

Area affected: 58724 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-Sep-09_to_2025-Sep-13_124.5_0.5

Heat wave occuring from September 09 2025 to September 25 2025 at -26.5°S 217.5°E

Download data: JSON

Event type: Heat wave

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

  • French Polynesia

Duration: 17 days

Time span: September 09 2025 to September 25 2025

Statistics over entire affected area:

  • Mean temperature anomaly: 1.8 °C
  • Mean temperature: 20.0 °C
  • Maximum temperature anomaly: 3.5 °C
  • Maximum temperature: 27.3 °C

Event center: -26.5°S 217.5°E

Area affected: 3113254 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-Sep-09_to_2025-Sep-25_217.5_-26.5

Heat wave occuring from September 08 2025 to September 18 2025 at 36.5°N 104.5°E

Download data: JSON

Event type: Heat wave

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

  • China

Duration: 11 days

Time span: September 08 2025 to September 18 2025

Statistics over entire affected area:

  • Mean temperature anomaly: 4.7 °C
  • Mean temperature: 21.0 °C
  • Maximum temperature anomaly: 8.5 °C
  • Maximum temperature: 30.5 °C

Event center: 36.5°N 104.5°E

Area affected: 644619 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-Sep-08_to_2025-Sep-18_104.5_36.5