New research conducted on 100 inhabitants of Tromso, Norway, where it is permanently dark for two months of the year, showed that people's reaction time, memory and attention span actually improved in the winter.
The study, conducted by Dr Tim Brennen of Tromso University, showed that verbal fluency was the only test for which people performed better in the summer. Dr Brennen said the widespread belief that people got groggier and more forgetful in the winter was unfounded.
"There is much research to show the mood swings and depression brought about by a lack of sunlight - known as seasonal affective disorder or SAD - but the effect on cognitive function was not known," he said. "Although the differences in thinking ability are modest, the majority are winter advantages."
The findings showed that people had slightly faster reaction times in the winter - a hundredth of a second faster - and were better at remembering lists of words. However, Dr Brennen warned that the differences were modest and were not a basis for moving examinations from summer to winter.
Dr Brennen said Tromso was an ideal place in which to conduct the studies as it was 200 miles north of the Arctic Circle and for two months in winter the sun failed to rise and temperatures fell to minus 18C.
"The message here is that performance is very similar in winter and summer. And just because you might feel miserable in winter, it does not necessarily mean you cannot perform," he said.