A typical meteorological year (TMY) is a data set of representative hourly weather for one typical year at a given location. The name 8760 comes from the number of hours in a year, and an 8760 file usually holds both the hourly TMY weather and the expected energy output for a full year. Designers feed TMY data into modelling tools such as PVsyst or SAM to predict site performance before construction. A typical TMY-based file holds plane-of-array irradiance, ambient temperature, wind speed and the expected power or energy under ideal conditions. Module temperature and global horizontal irradiance columns may also be included. Monitoring platforms can import the 8760 file to calibrate their PV model against the original design, for example by working out an inverter derate. TMY3 is a version drawn from the nearest TMY3 station, and TMY data sets in the US are derived from the National Solar Radiation Data Base. For long-term performance checks, the weather actually measured on site can be converted into the TMY input format and run through the original model to get expected energy.
related_toTMY or 8760 data sets are used as the weather input to PVsyst when predicting performance during design.
sec=front h=ed201c211c7csec=h20 h=a40e86dc651bsec=h4 h=134a0a82052cc2 drafted · lead System Advisor Model
Performance models such as SAM take weather input in a format such as TMY.
sec=h20 h=a40e86dc651bc3 drafted · lead Expected energy model
8760 files carry expected hourly energy for a full year. They are used to align a monitoring PV model with the original design.
sec=front h=ed201c211c7csec=h20 h=a40e86dc651bc4 verified · fact Energy yield assessment
8760 values come from modelling software before a project is built and estimate hourly generation for the first year.
sec=front h=ed201c211c7csec=front h=62ba5b7d5da9verified by: review-workflowverified on: 2026-10-24
c5 drafted · lead AlsoEnergy PowerTrack platform and API
PowerTrack can import a TMY (8760) file as reference data and work out a derate value for each inverter.
sec=front h=ed201c211c7cc6 drafted · lead Plane-of-array irradiance
A TMY file imported into PowerTrack must contain POA irradiance.
sec=front h=ed201c211c7cc7 drafted · lead Global horizontal irradiance
An 8760 import can include a global horizontal irradiance column (globhor).
sec=front h=ed201c211c7cc8 verified · fact National Solar Radiation Database proposed
TMY data sets are derived from the NSRDB. NSRDB TMY3 is used as a weather file.
sec=4.1.1 h=9129b8f4a6f2sec=h4 h=134a0a82052cverified by: review-workflowverified on: 2026-10-24review note: support check: partial - u25 says TMY data sets derive from the NSRDB and u30 uses NSRDB TMY3 weather file, but u25 refers specifically to the 1961-1990 NSRDB; the general claim is roughly supported.
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