You probably know how much your body reacts to the seasons. A cold snap can leave your hands feeling stiffer in the morning, and winter has a way of making old aches feel louder.
For people with psoriatic arthritis, that feeling may be more than imagination. A large Dutch study of nearly 1,000 patients found that joint flares tend to run higher in the colder months, especially winter and autumn.
Researchers at Erasmus Medical Center in Rotterdam, led by Batoul Hojeij, tracked 935 newly diagnosed patients over three years and matched their records against official weather data. The study was published in RMD Open on October 23, 2026.
What the researchers tracked over three years
The team used the Dutch South West Psoriatic Arthritis cohort, known as DEPAR, which has followed patients at hospitals across the Netherlands since 2013. Doctors recorded swollen joints, pain scores and mood. Weather data came from the Royal Netherlands Meteorological Institute.
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When patients were first diagnosed, the season made no clear difference to how active their disease was. The pattern only showed up during the three-year follow-up, after patients had started treatment.
Using a standard disease measure called DAPSA, the team found that winter, spring and autumn all carried higher disease activity than summer. Winter was linked to more swollen joints and a higher C-reactive protein, a blood marker of inflammation.
Autumn stood out for worse pain scores.
Why specific weather factors did not explain it
The team also looked at temperature, humidity, wind speed, air pressure and sunshine hours. None of those single measurements lined up neatly with worse symptoms.
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In other words, the season mattered, but no single weather number explained why. The authors suggest the drivers could be more indirect, such as seasonal infections, changes in lifestyle during winter, or air pollution.
What this means for patients this winter
The National Psoriasis Foundation notes that many people with psoriasis and psoriatic arthritis experience flares in winter or summer. Dry indoor air, colds and flu, long hot showers and stress can all play a role.
The Dutch team stops short of changing clinical guidelines. They recommend that doctors recognize seasonal fluctuations in disease activity, particularly in winter and autumn when symptoms seem to run higher.
For the roughly 1 million US adults diagnosed with psoriatic arthritis, according to the CDC, the practical takeaway is simple. A winter check-in with the rheumatologist may be worth putting on the calendar, even after a stable summer.
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This article is made and published by Mie Hermansen, who may have used AI in the preparation.