Weather Data Viewer

Weather Data Viewer logo.

Displays actual design values, coincident/joint frequency tables, or summary statistics for dry bulb, dewpoint, wet bulb, enthalpy (H), and wind speed for the locations given in the climatic design information chapter of the 1997 ASHRAE Handbook - Fundamentals (HOF). Design conditions were determined for 509 US, 134 Canadian, 339 European, 293 Asian and 169 other worldwide locations for a total of 1444 locations. Thirty-three years of hourly weather data were used for approximately 1/2 of the US and all of the Canadian locations. Twelve years of data were used for the other locations. The data went through quality checking and short-term linear interpolation filling processes. Months which had sufficient data were then used in the analysis. The data were analyzed to produce annual frequency-of-occurrence design dry-bulb (DB), wet-bulb (WB) and dew-point (DP) temperatures with mean coincident values at the design conditions. Additional description on the software is given on the ASHRAE TC 4.2 web page. Screen Shots


weather, climate, extreme weather, design data, design temperature, humidity, dew point, dry bulb, wet bulb, temperature, enthalpy, wind speed



Expertise Required

Student or engineer of HVAC system design. Low level of computer literacy required.


Worldwide distribution and use.


Researcher, student, or HVAC system design engineer


Location data sets are selected using the Data Selection dialog box. The items that need to be selected are:

  • General Location (US, Canada, Europe, Asia, Other)
  • Specific Location (from menu list)
  • Units desired (SI/IP)
  • Type of output desired
  • Parameters to be displayed
  • Time period of interest
  • Output headers


Heating, cooling and/or enthalpy design values, cumulative frequency value and the mean coincident value (DB/DP, DB/WB, DB/H, and DB/WS) and vice-versa, 2-D joint frequency/coincident matrix in 1 degree F bins for 1444 locations. Six levels of output can be selected for combinations of the four psychrometric parameter pairs for annual and monthly calendar periods. The file output of the viewer can be displayed, saved to a file (space or comma delimited format) or printed as standard data text or as comma delimited data.

Computer Platform

Windows 3.1 or later; 8MB RAM; 1MB hard disk space for minimum installation, approximately 1.3 GB for complete installation. PC-compatible only; not intended for network installation.

Programming Language



The CD-ROM allows you to create your own custom bin weather data for the 1444 locations by specifying the specific hours of the day, days of the week, and months of the year to include in the binning. This program also provides the capability to:

  • Select the bin size, such as 2F, 5F or 10F
  • Use parameters other than just dry bulb temperature, such as humidity ratio, wet bulb, etc.
  • Determine the average value of other parameters, which occurs coincident with that of the binned parameter. For example, determine the average enthalpy coincident with a 75F and 80F dry bulb bin.
  • Copy a TMY2 record from the CD-ROM for use in an hourly energy analysis program.


A comparison with the previous design values indicated that the new dry bulb and wet bulb design conditions are slightly less extreme than the values previously published. However the new design dew point values indicate the potential for significantly more extreme dehumidification design conditions than would be found by using the old extreme dry-bulb temperature with mean coincident wet-bulb temperature.





1791 Tullie Circle, NE
Atlanta, Georgia 30329
United States


+1 (800) 527-4723 US/CAN +1 (404) 646-8400


+1 (404) 321-5478




ASHRAE's Weather Data Viewer is available for $99 ($79 for members of ASHRAE). Order on the web at Order by phone by calling ASHRAE Customer Service at 1-800-527-4723 in the U.S. and Canada, or at (404) 636-8400 worldwide. Fax your order to (404) 321-5478. Questions about this or other ASHRAE products should be e-mailed to