Water Resources: Reservoirs at Their Highest Since 2024, Caution Remains Essential
With a filling rate of 65% as of December 31, the seven main surface reservoirs are at their highest level since 2024. This is a welcome relief, but authorities urge caution in light of uncertain climate forecasts.
Currently, the numbers are reassuring. On the last day of 2025, the seven main surface reservoirs in Mauritius had a filling rate of 65%, compared to 45.9% at the same time in 2024. This significant improvement is attributed to the late-year rains, allowing the island to start 2026 in a more favorable water situation than in recent years.
Mare-Longue leads with 86.1% full, followed by Bagatelle (78.7%) and Midlands (65.4%). Mare-aux-Vacoas and Piton du Milieu are at 63.5%, La Nicolière at 58.6%, while La Ferme brings up the rear with 41.8%.
These positive results can be explained by the rainfall recorded in the last days of 2025, with precipitation ranging from 35 to 81.3 millimeters in 24 hours in some areas. Groundwater levels are also expected to benefit from this influx, although data is yet to be confirmed. The latter half of December was notably marked by heavy rains, prompting the Mauritius Meteorological Services (MMS) to issue several alerts. This contrasts sharply with forecasts released in November, which predicted below-normal precipitation for the first half of the austral summer, from November 2025 to January 2026.
November already defied expectations. The month recorded 140 millimeters of rain, or 165% of the long-term average. The eastern region was particularly drenched, receiving 247 millimeters, reaching 227% of the normal. The first half of December continued this trend, totaling 83 millimeters, or 122% of the long-term average, with a peak of 149 millimeters in the Central Plateau (166% of regional normal).
A Fragile Respite
Despite these higher-than-expected rainfall contributions, the filling rate of the reservoirs paradoxically decreased from December 1 to 30, 2025, slipping from 68% to 65%. This modest decline is telling: consumption continues to exert pressure on water resources, even when the weather is favorable.
Mauritian authorities thus call for caution. Rigorous management of water resources and responsible usage by the population remain essential, they emphasize. The goal is to avoid falling back into the difficult situations experienced in recent years, characterized by deficient rainfall and sometimes severe water restrictions.
Additionally, seasonal forecasts suggest a national rainfall total slightly below average for the entire austral summer (November 2025 to April 2026), around 85% of normal, or about 1,150 millimeters. Without significant new rainfall, authorities warn that prudent water usage remains crucial to prevent potential cuts if the downward trend continues.
Another concern is temperatures. In January, the MMS predicts values slightly above seasonal norms, potentially exceeding long-term monthly averages by two to three degrees Celsius. Highs could reach 36°C along the coasts, particularly in the west. More concerning, the combination of high temperatures, prolonged periods of high humidity, and low winds, mainly between January and March 2026, could lead to heatwave conditions. This situation is likely to cause significant discomfort, especially for the most vulnerable groups: the elderly, young children, and those with chronic illnesses.
Thus, Mauritius enters 2026 with well-filled reservoirs, but in a climate context that remains uncertain. Amid unpredictable rains and forecasted heat, the island balances cautious optimism with necessary vigilance, aware that water security remains a major issue in the face of climate change.
Good Rainfall at the End of 2025
The island received substantial rainfall during the last days of December 2025, with precipitation between 35.0 mm and 81.3 mm recorded within 24 hours from 4 AM on Tuesday, December 30, to 4 AM on Wednesday, December 31. The areas most affected were:
• Le Morne: 81.3 mm
• Mare-aux-Vacoas: 53.3 mm
• Vacoas: 51.6 mm
• Rivière-Noire: 48.2 mm
• Bell-Village: 35.9 mm