Year
A year was the amount of time it took for a planet to orbit its sun. If the planet had an axial tilt, this resulted in seasons, like winter, spring, summer, and fall.

It took the colony ship  nine years to get to the planet Terra Nova to form the Terra Nova colony in 2078. ()

Sub-commander T'Pol stated in 2151, that she was not familiar with the early years of Earth space exploration. ()

The Vulcan monastery at P'Jem was almost 3,000 years old as of 2151. According to the Vulcan elder at the monastery, the reliquary wasn't entered in years and the transmitter also hasn't been used for years. ()

With a warp three engine, a cargo freighter could cut down a five year cargo run down to six months. ()

Nausicaan pirates were attacking freighters in a specific sector for years until 2151. ()

Standard UFP solar year 
Standard UFP solar years were mentioned in the Treaty of Armens. (, okudagram)

Earth year 
One Earth year was a span of time equal to 365.2425 Earth days.

Captain Jonathan Archer suggested that Bernadette Fuller was around seventy-five Earth years in 2151 while talking to Nadet. ()

According to Doctor Phlox, Travis Mayweather was twenty-six Earth years during his autopsy in 2152. ()

External link 
 
Time measurements