Daily mean temperatures at the Crater Lake since 2020 with the coolong trend (image: GNS Science/GeoNet )The Crater Lake usually experiences two to three heating and cooling episodes within any 12-month period. During these cycles, the lake temperature typically rises to 30–40 °C before cooling back to 10–15 °C. Since reaching 41 °C in May 2022, there have been five subsequent heating episodes, with each peak—except one—lower than the previous, indicating an overall downward trend in maximum lake temperatures.The most recent cycle began at 10 °C in early July and peaked at only 17 °C in late August before declining again. The lake is currently 13 °C.Although the three-year trend shows progressive cooling, substantial volumes of volcanic gas continue to be released from the active vent beneath the lake. This demonstrates that an open pathway persists between the magma source and the lake, allowing gas to escape and reducing the likelihood of pressure buildup beneath the crater.We interpret the reduced heating to mean that recent gas and heat pulses entering the lake are becoming shorter in duration and/or smaller in volume, preventing the lake from reaching the previously common 30–40 °C range.As the lake cools, steam and hot gas input decreases, disturbing less sediment. Consequently, the lake colour is expected to shift from grey to blue-green as suspended sediment settles. Minor upwellings of hot water and yellow sulphur slicks will, however, remain visible at the surface.Other monitoring indicators—including earthquakes, tremor, gas emissions, and lake chemistry—are all within normal ranges. Overall, Mt Ruapehu continues to display typical low-level activity consistent with minor volcanic unrest. The Volcanic Alert Level remains at 1, and the Aviation Colour Code remains Green.