Researchers reckon youngsters are more influenced by how light it is rather than what the weather is like when they decide whether or not to play outside.
This has led to boffins concluding that by not changing the clocks, kids would have more opportunity to play outside, and therefore become fitter.
The research, published in the Journal of Physical Activity and Health, looked at the activity levels of 325 children in south-east England aged between eight and 11.
The youngsters wore accelerometers to record the amount of exercise they did, along with keeping a diary of their activities.
Researchers at the London School of Hygiene and Tropical Medicine and University College London discovered the children did more exercise outside on longer days, particularly at the end of the day during summer, regardless of whether it was rainy, windy or cloudy.
Dr Anna Goodman from the London School of Hygiene and Tropical Medicine said the study provided "the most direct evidence yet that changing the clocks so that there is more daylight in the afternoon could increase children's physical activity."
She told the BBC: "The fact that kids spend more time playing outdoors and are more physically active overall on these longer days could be important at a population level for promoting their fitness and in preventing child obesity. This strengthens the public health argument for the Daylight Saving Bill currently under consideration by the House of Commons, which proposes putting the clocks forward by an extra hour all year round."
What do you think? Yet another 'makes kids fat' study stating the obvious - most children aren't allowed to play outside in the dark?