Typical year

From Glossary of Meteorology

typical year

The 12 months, January–December, selected from the entire period of record span for a given location as the most representative, or typical, for that month.

Thus, for a given station, a typical year will be a composite year with, possibly, each month of data from a different calendar year. As applied to the building construction and energy management industries, a typical meteorological year (TMY) consists of a full set of 8760 hourly weather observations (365 days × 24 h) containing real weather sequences that represent the long-term climatic modal (i.e., most frequent) conditions for a particular location. The hourly data include extraterrestrial, global and direct solar radiation estimates and observed ceiling, sky cover, visibility, weather (type), sea level and station pressure, dry-bulb and dewpoint temperatures, cloud amounts, and total and opaque sky cover. TMY data have been utilized, for example, by engineers in the design and evaluation of energy systems.