From HVAC: The Handbook of Heating, Ventilation and Air Conditioning for Design and Implementation


This chapter provides tables of climatic conditions for locations in the United States, Canada, and around the world. The data for this chapter have been adapted from 2001 ASHRAE Fundamentals Handbook, "Weather Information", which in turn was developed from information available in previous ASHRAE Handbooks and publications.

As is evident from the chapters in this handbook, climatic data is needed for design, sizing, distribution, installation, and marketing of heating, ventilating, air-conditioning, dehumidification and smoke management equipment, as well as for other energy-related processes in residential, agricultural, commercial, and industrial applications. Warm-season temperature and humidity conditions correspond to annual percentile values of 0.4, 1.0, and 2.0. Cold season conditions are based on annual percentiles of 99.6 and 99.0. The use of annual percentiles to define the climatic design conditions ensures that they represent the same probability of occurrence anywhere, regardless of the seasonal distribution of extreme temperature and humidity.

Climatic Design Conditions

Annual design conditions for the United States appear in Table 19-1, for Canada, in Table 19-2, and for international locations, in Table 19-3.

The information provided in Tables 19-1 to 19-3 in the indicated column is from left to right is:

  1. Name of station

  2. Location (location, longitude, and elevation)

  3. Heating dry-bulb temperature corresponding to 99.6%, and 99%

  4. Cooling dry-bulb and mean wet-bulb temperature corresponding to 0.4%, 1.0%, and 2.0%

  5. Evaporation dry-bulb and mean wet-bulb temperature corresponding to 1.0%, and 2.0%

  6. Dehumidification dewpoint, humidity ratio and mean dry-bulb temperature corresponding to 1.0%, and 2.0%

  7. Mean daily range,...

Products & Services
Gas and Vapor Barriers
Gas and vapor barriers are used on the exterior of buildings to allow air flow, but limit the passage of moisture.
Environmental Exposure (Climatics) Testing Services
Environmental exposure (climatics) testing services use humidity, pressure, temperature, vibration, exposure to ultraviolet light (UV) and other climatic variables to test samples, parts and components, and finished products.
Weather Instruments
Weather instruments are designed to measure one or multiple components of weather including wind speed and direction, rain or snow fall, solar radiation, temperature, pressure and humidity.
Dial Thermometers
Dial thermometers are bimetal or bi-metallic, liquid or gas-filled, and vapor-tension-based. These devices display temperatures in Fahrenheit, Celsius, or both.
Downdraft Tables
Downdraft tables are self-contained, portable filtration systems that remove harmful particulates and return filtered air.

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