Climate Change, Length of Extreme Heat Waves in Tahoua (Niger) during the Year 2024

Abstract

Extreme heat during the March-April-May hot season is an important climatic concern in Tahoua, Niger. This study assessed the duration of heatwaves in Tahoua city during 2024 using daily maximum temperature observations from the Tahoua station. Two identification approaches were compared: the absolute 40°C threshold used by ACMAD, under which a heatwave occurs when the maximum temperature exceeds 40°C for at least three consecutive days, and percentile-based thresholds at the 85th, 90th, and 95th percentiles. The threshold approach identified eight periods of sustained high temperature during March-April-May, including several episodes lasting at least three consecutive days. The percentile analysis showed that estimated heatwave duration depended strongly on the selected percentile. At the 95th percentile (43.7°C), one heatwave episode lasting 5 days was identified. At the 90th percentile (42.8°C), four heatwave episodes lasting 4–9 days were recorded. At the 85th percentile (41.6°C), six episodes lasting 3–19 days were identified, including longer events from late March to early April and from late April to early May. These results demonstrate that the estimated number and duration of heatwave episodes in Tahoua during 2024 varied with the operational threshold used. The findings provide a station-level description of extreme-heat duration during the 2024 hot season and support careful selection of percentile or absolute thresholds when characterising heatwave conditions in Tahoua.