TMY Typical Meteorological Year (or DRY Design Reference Years)

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TMY Typical Meteorological Year (or DRY Design Reference Years)

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Typical Meteorological Years (TMY) or Design Reference Years (DRY) are meteorological hourly data files constructed on the basis of real measured data series. The elaboration of DRY or TMY obeys a sophisticated normalized procedure. It usually consists of a juxtaposition of selected months, chosen among 10 years or more of real measurements, according to several statistical criteria, and approaching average values. The month's extremities are eventually corrected for harmonious continuations, and these data sets should also include realistic extreme behaviors. They are constructed so that the whole year reproduces a typical meteorological situation for the design of energetic or architectural systems.


PVsyst does not use DRY to construct meteorological hourly data files. The method used is the synthetic data generation from the meteonorm algorithm.


In Switzerland, the ANETZ measuring network has elaborated 22 DRY files with measurements coming from the Swiss Institute for Meteorology, and according to a procedure elaborated by the International Energy Agency (IEA), task 9, sub-task E.

For other European locations, DRY may sometimes be obtained at the addresses given below. These data are not necessarily prepared according to the same standards: some of them are referenced as "Test Reference Years" (TRY), and follow a similar method approved by the European Communities. German data are specified by the Free University of Berlin.  The  1035  TMY3  files for the USA were prepared by the NREL.

Here is a list of institutions where hourly meteo data may eventually be available  (state 1994 - probably many of them obsolete !):



Institut Royal Météorologique

3, av. Circulaire, B-1180 Bruxelles


Cenergia ApS

Sct. Jacobsvej 4, DK-2750 Ballerup


Direction de la Météorologie

2, avenue Rapp, F-75340 Paris Cedex 07


Berlin University

University of Berlin


Meteorological Service

Glasnevin Hill, IRL - Dublin 9


National Research Council

Via Nizza 123, I-00198  Roma.

The Netherlands:


P.O.Box 201, NL-3730 AE De Bilt


IPMA (former INMG)

Rua C do Aeroporto, P - 1749 - 077 Lisboa


Katedre KPS

Stavebena Technika Universita, SL-813 68 Bratslava



Ueberlandstrasse 129, CH - 8600 Dübendorf


Tübitak, Building Research Inst.

221, Atatürk Bulvari, Ankara

United Kingdom:

Meteorological Office, MET.0.1

Eastern Road, Bracknell, Berkshire RG12 2SZ, UK


1035 TMY data files which can be directly imported in PVsyst.