The Subboreal, the second before last climatic period of the Holocene, lasts from 3710 to 450 BCE.

The Subboreal replaces the Atlantic and is followed by the Subatlantic.

In paleoclimatology, the Subboreal is divided into an Older Subboreal and a Younger Subboreal.

Historically the Subboreal is equivalent to most of the Neolithic and the entire Bronze Age, which started 4200 to 3800 years ago.

The boundary between the older and the younger Subboreal is equated as 1350 BCE, when meltwater pulse (IA) raised sea level by about twenty-five meters, or seventy-five feet.

The Subboreal is equivalent to W. H. Zagwijn's pollen zones IVa and IVb and T. Litt's pollen zone VIII.

In the pollen scheme of Fritz Theodor Overbeck it occupies pollen zone X.European beech (Fagus sylvatica) and hornbeam (Carpinus betulus) immigrated from their retreats on the Balkan and south of the Apennines.

This happened also diachronously—beech pollen are found for the first time in the interval 4340 to 3540 years BCE and hornbeam pollen somewhat later between 3400 and 2900 years BCE.

The start of the Younger Subboreal coincides with the massive spreading of beech from their origins in the Balkan and south of the Appeninces.

The establishment of beech and hornbeam is accompanied by indicator plants for human settlements and agriculture like cereals and plantain (Plantago lanceolata), at the same time hazel is receding.

The relatively dry climate during the subboreal furthers the spreading of heath plants (Ericaceae).