Our use of artificial light has fooled flowers and plants into thinking Spring has come early.
Researchers at the University of Exeter have found that buds were bursting up to seven days earlier in brighter areas.
Scientists compared the amount of artificial night-time light across the country with the date new leaves first appeared on trees such as sycamore, oak, ash and beech.
It drew on "citizen science" data from the Woodland Trust, which asked members of the public to record the signs of the changing seasons, such as bud-burst, in its Nature's Calendar scheme.
When they compared 13 years of data they found the key signs of spring were occurring up to seven and a half days earlier in brighter area.
The effect was larger in later budding trees.
Researchers were also able to rule out the so-called "heat island" effect, where plants bud earlier due to the slightly warmer climates in cities.
The way the effect was seen across all areas suggested it was not down to temperature rises, according to the study, which was a collaboration between the university and independent environmental consultants Spalding Associates, in Truro.
The scientists raised concerns that the impact of artificial night-time lighting - such as street lights - on trees would have a knock-on effect on other wildlife.