Study from UBC its pointing that summer is getting longer, and it’s happening faster than we thought

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A new study from the University of British Columbia reveals that summers are expanding more rapidly than previously measured. Between 1990 and 2023, the average summer lengthened by about six days per decade—50% faster than earlier estimates. In some cities, the change is dramatic: Sydney’s summer now lasts around 130 days compared to 80 in 1990, while Toronto’s has grown by eight days per decade.

Image by Sindre Fs on Pexels

Researchers defined summer not by calendar months but by weather thresholds, using historical climate data from 1961–1990. They found that seasonal transitions are becoming more abrupt, with sudden shifts from spring to summer and summer to autumn. This disrupts ecological and human systems, affecting agriculture, water supply, public health, and energy planning.

The study also introduced a new metric for cumulative summer heat, showing that heat accumulation in the Northern Hemisphere has risen more than three times faster since 1990 compared to earlier decades. Coastal regions are experiencing some of the fastest growth, raising concerns for millions living in areas once considered moderate.

The findings highlight urgent questions about food security, extreme weather timing, and whether current climate models adequately capture these accelerating changes. Overall, the research underscores that the rhythm of the seasons is shifting more quickly than expected.

“These findings challenge what we believe to be the normal cycle of the seasons,” said lead author Ted Scott, a PhD student in UBC’s department of geography. “When summer happens and how quickly it arrives impact patterns and behaviours in plant and animal life, and human society.”

Seasons are changing gears more quickly
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The study also found that seasonal transitions—the shift from spring to summer and from summer to autumn—are becoming more abrupt. Instead of a gradual warm-up, summer-like temperatures arrive more suddenly. This could disrupt systems that depend on seasonal cues; for example, flowers may bloom before pollinators are active, crops may need to be planted earlier, and rapid spring warming may lead to faster snowmelt and greater spring flood risk.

“The changes may be very disruptive to a wide range of systems,” Scott said. “An expectation in the Northern Hemisphere that June is when summer starts may be ingrained in planning and policy, meaning we could be ill-prepared for earlier heat.”

The heat is adding up—faster than before
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The study, was published last Tuesday in the journal Environmental Research Letters, also introduces a new way of measuring cumulative heat that builds up over a summer, combining temperature and time. By this measure, accumulated summer heat over Northern Hemisphere land is rising more than three times faster since 1990 than it did from 1961 to 1990.

The study found that coastal areas in the Northern Hemisphere are seeing some of the fastest growth in summer length and accumulated heat, which could affect millions of people who have moved to these areas in part because of their perceived moderate climate.

Scott and co-authors Dr. Rachel White, professor in the department of earth, ocean, and atmospheric sciences and Dr. Simon Donner, professor in the department of geography and the Institute for Resources, Environment and Sustainability, analyzed temperature data spanning 1961 to 2023 across land, ocean and coastal zones in both hemispheres, and examined trends in 10 cities around the world.

Citation
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The study Summers over land and ocean are becoming longer, transitioning faster, and accumulating more heat was published in the journal Environmental Research Letters. Authors: Ted J Scott, Rachel H White and Simon D Donner.

Summers over land and ocean are becoming longer, transitioning faster, and accumulating more heat Ted J Scott*, Rachel H White and Simon D Donner

Published 7 April 2026 • © 2026 The Author(s). Published by IOP Publishing Ltd Environmental Research Letters, Volume 21, Number 7 Citation Ted J Scott et al 2026 Environ. Res. Lett. 21 074009 DOI 10.1088/1748-9326/ae5724

The article Summer is getting longer, and it’s happening faster than we thought, signed by Erik Rolfsen was published yesterday on UBC’s news section.
Here, in Notaspampeanas we republished some of the original article. There is a Spanish translate. Many thanks to UBC, UBC researchers and the journal Environmental Research Letters.

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