Phenology from other seasons, such as autumn, is more complicated and may be because of knock-on effects from spring.
However, from all the data gathered by Nature’s Calendar, there are clear trends to changing timescales in our phenology in spring and autumn.
And those changes are in part a consequence of warmer seasons.
While spring is the fastest-warming season, all four seasons have warmed since 1970.
Met Office analysis suggests for every 1C increase in October temperature, the date at which trees lose all their leaves is delayed by about two or three days.
And climate change is leading to more extreme weather which is also causing confusion amongst some species.
“It’s the unpredictability which is the biggest threat at the moment,” says Ms Marshall.
With each tree, flower, fruit or animal species reacting slightly differently to our changing climate, there may become a mismatch of events.
This could lead to a disruption in the food chain to some of our species and put them under pressure in the future.