In phenology, season creep is a neologism that refers to observed changes in the timing of the seasons, especially earlier indications of spring widely observed in temperate areas across the Northern Hemisphere. Phenological records analyzed by climate scientists have shown significant temporal trends in the observed time of seasonal events, from the end of the 20th century and continuing into the 21st century. In Europe, season creep has been associated with the arrival of spring moving up by approximately one week in a recent 30 year period. Other studies have put the rate of season creep measured by plant phenology in the range of 2–3 days per decade advancement in spring, and 0.3–1.6 days per decade delay in autumn, over the past 30–80 years.