Weather Data for Simulation

Users of energy simulation programs have a wide variety of weather data from which to choose – from locally recorded weather data to preselected 'typical' years –, often a bewildering range of options. Many locations are available on this site – but users may have special needs for different locations. This page lists sites that may provide those other user locations. Before tapping the resources below, users should check if an existing EnergyPlus Weather Format (EPW) file is within 20-30 miles (30-50 km) and within a few hundred feet (100 m) of elevation.

There are a few things to consider before jumping to obtain weather data merely because your location is not supplied. Users of energy simulation programs should avoid using single year, Test Reference Year-type (TRY) weather data. No single year can represent the typical long-term weather patterns. More comprehensive methods that attempt to produce a synthetic year to represent the temperature, solar radiation, and other variables within the period of record are more appropriate and will result in predicted energy consumption and energy costs that are closer to the longterm average. Both Typical Meteorological Year 2 (TMY2) and Weather Year for Energy Calculations 2 (WYEC2) use this type of method, are based on improved solar models, and more closely match the long-term average climatic conditions.

More information on selecting weather data appropriate for energy simulation is described in this paper Drury B. Crawley. 1998. "Which Weather Data Should You Use for Energy Simulations of Commercial Buildings?" in ASHRAE Transactions, pp. 498-515, Vol. 104, Pt. 2. Atlanta: ASHRAE.

Some private sources that supply simulation appropriate weather data:

  • Weather Bank - WeatherBank maintains hourly and daily historical data records from every National Weather Service reporting station in the United States, as well as other locations around the world. They archive weather data on a real-time basis and certain updates are made hourly. This hourly archiving began in late November, 1994.

  • National Center for Environmental Information - National Center for Environmental Information (NCEI) is the world's largest active archive of weather data. NCEI produces numerous climate publications and responds to data requests from all over the world. NCEI operates the World Data Center for Meteorology which is co-located at NCEI in Asheville, North Carolina, and the World Data Center for Paleoclimatology which is located in Boulder, Colorado.

  • Weather Source - Weather Source provides historical and real-time digital weather information for more than 10,000 locations across the United States and around the world.

  • Weather Analytics - Site specific weather files in EnergyPlus format based on your choice of the most current 30, 15, or 10 years of hourly data are now available from the private sector company Weather Analytics for any official weather station on more than 650,000 35-km grid tiles across the globe. These files are built by integrating hourly weather station observations and the new NOAA reanalysis data sets. Both Typical Meteorological Year (TMY) files and individual, Actual Meteorological Year (AMY) files are available, as are files constructed from the previous 12 months.

  • Meteonorm - Meteonorm delivers typical meteorological years for any place. Either the software – including data for the whole world – or single datasets in EnergyPlus format can be bought from Meteotest. Meteonorm is a combination of a climate database and a weather generator. The radiation database - a mixture of ground and satellite data – includes long term monthly averages. Daily, hourly or minute values are generated stochastically. In addition to global radiation, the software includes 38 parameters like humidity and temperature. Hour-to-Hour and day-to-day variability and distributions are modeled as realistic as possible – but may include deviations from measured data.

  • White Box Technologies - WBT provides instant web access to the following weather data sets that are immediately ready for use in EnergyPlus:

    1. ASHRAE IWEC2 (International Weather for Energy Calculations) "typical year" weather files for 3,012 international locations outside of US and Canada. IWEC2 weather files can be purchased online either individually, in country and region sets, or even the entire set of 3,012 in alternate formats such as *.epw or *.BINM. For a complete list of all 3,012 IWEC2 files, please see: . IWEC2 weather files were developed in a 4-year ASHRAE research project (RP-1477), and distributed by WBT on agreement with ASHRAE. The IWEC2 weather files come in these three standard formats: *IW2.CSV, *.BINM, and *.EPW + *.DDY.

    2. Historical year weather files from 2001 through the current year for over 10,000 stations around the world, including over 2,000 US and 400 Canadian stations (earlier years are also available upon request). For a complete list of all 2015 files, please see: or These historical year weather files cost were developed using similar raw data and processing software to the IWEC2 files. The historical year weather files come in thhese three standard formats: *_FIN4.TXT , *.BINM, and *.EPW + *.DDY.

    Both data sets are based on actual recordings from official weather stations around the world going back up to 25 years and archived as the Integrated Surface Hourly Database (ISD) by the (US) National Center for Environmental Information (NCEI). Extensive processing equivalent in scope to the TMY3 files has resulted in complete weather files with solar radiation, daylight illuminance, and precipitation, in addition to the standard parameters of temperature, humidity, pressure, wind speed and direction, etc. For more details, please go to: