Summertime temperature extremes exert profound impacts on human health, ecosystems, and infrastructure, yet their characteristics and drivers remain poorly quantified in New Zealand, in part due to the country's complex topography and multiple climate regimes. Using high‐quality temperature observations from 30 weather stations spanning 1980–2022, this study examines the capability of a commonly used global reanalysis product,...

The computational cost of dynamical downscaling limits ensemble sizes in regional downscaling efforts. We present a generative-AI approach to greatly expand the scope of such downscaling, enabling fine-scale future changes to be characterised including rare extremes that cannot be addressed by traditional approaches. We test this approach for New Zealand, where heterogenous regional climate effects are anticipated. End-of-cent...

Marine heatwaves (MHWs) are increasingly prevalent oceanic extremes with the potential to influence adjacent weather and climate over land. This study characterizes the spatio‐temporal variability of MHWs surrounding New Zealand from 1982 to 2020 and examines their relationship with concurrent terrestrial temperature and rainfall anomalies, alongside the broader synoptic‐scale circulation. This observational analysis reveals a...

Heat extremes over large continental regions are often intensified by depleted surface soil moisture, yet the role of land–atmosphere coupling over small island nations like New Zealand remains underexplored. Here, we present the results of bespoke regional climate model experiments designed to quantify the contribution of coincident dry soils to the severity of recently observed hot summer months over New Zealand. Specificall...

Marine heatwaves (MHWs) adversely impact Aotearoa New Zealand’s marine ecosystems and pose challenges for resource management. In this study, we evaluate forecast skill of monthly MHWs and sea surface temperature (SST) anomalies using a multi-model ensemble (MME) comprised of nine general circulation models and 206 members with a focus on Aotearoa New Zealand for the first time. Over the hindcast period (1993–2016), the MME ou...

Dynamical downscaling provides physics-based high-resolution climate change projections across regional and local scales. This is particularly important for island nations characterized by complex terrain, where the coarse resolution of global climate model (GCM) output often prohibits direct use. One of the main motivations for dynamical downscaling is to reduce biases relative to the host GCM at the local scale, which can be...