State-level analysis finds Alaska and the US interior warming fastest since 1980

A new open-access study in Scientific Data reports how strongly daily maximum temperatures have risen in each US state in step with global warming between 1980 and 2022. Researchers at the MIT Center for Sustainability Science and Strategy (CS3) found the steepest average trends in Alaska, Utah, New Mexico, Colorado and Nevada. The weakest were in Hawaii, Montana, North Dakota, South Dakota and Arkansas.

Why regional detail matters

Global warming, measured against the 1850-1900 baseline, currently stands at about 1.63 degrees Celsius. That figure is an average, and local temperatures do not rise uniformly around the world. Places where trends are strongest face the greatest pressure on ecosystems, crop production, buildings and infrastructure, human health and local economies. Adaptation planning therefore depends on knowing which areas are changing fastest, and by how much.

Data and approach

The team drew on two widely used, high-resolution climate and weather datasets, MERRA2 and ERA5, covering 1980 to 2022. Both are reanalysis products, which blend observations with models to produce consistent gridded records. From these, the researchers calculated warming trends attributed to global warming in the monthly average of the maximum daily temperature for each state.

The study differs from earlier work on US temperature trends in its level of detail. It aggregates average maximum, minimum and mean daily temperatures at the state level for every month of the year. The authors say this gives planners in government, industry and civil society information they can act on, rather than a single annual figure for a broad region.

What the trends show

Alaska recorded the largest historical warming in maximum daily temperature. Its monthly-averaged maximum rose by an average of 2.5 °C for each degree of global warming. Hawaii had the smallest response, at 0.8 °C per degree.

The pattern also varied through the year. Across the country, warming was most marked in summer and autumn, and particularly in September and November.

• Strongest average trends: Alaska, Utah, New Mexico, Colorado, Nevada
• Weakest average trends: Hawaii, Montana, North Dakota, South Dakota, Arkansas
• Seasonal peaks: summer and autumn, especially September and November

Implications for planning

The authors expect these state-by-state patterns to persist, barring unforeseen local anomalies, as human emissions continue to push up the global average. C. Adam Schlosser, deputy director of MIT CS3 and a co-author, said decision-makers should look at states with the steepest rises in maximum and minimum daily temperatures. The aim is to identify where continued trends could push natural resources, ecosystems and infrastructure past the thresholds at which they function safely.

Schlosser argues that, where that risk is greatest, triage and adaptive measures should come first. Directing resources to those places, he says, could substantially reduce both physical and financial climate risks.

Points for researchers

The results are scaled to global warming rather than presented purely as changes over time, which makes them easier to carry forward as global temperatures rise. They are also tied to two particular reanalysis datasets and to a 43-year window. Researchers using the state-level monthly figures for impact assessments may want to compare them with station records and other products. The seasonal and monthly breakdown could also support work on sector-specific questions, such as heat stress during the months showing the strongest trends, although the source does not describe such analyses.

Source: Study pinpoints states with steepest warming trends since 1980 (MIT News: research, 31 October 2026).

Image: AI-generated illustration.