This software can use an external Climate File that contains daily air temperature, evaporation, and wind speed data. The program currently recognizes the following formats:

A DSI-3200 or DSI-3210 file available from the National Climatic Data Center at www.ncdc.noaa.gov/oa/ncdc.html.

Canadian climate files available from Environment Canada at www.climate.weatheroffice.ec.gc.ca.

A user-prepared climate file where each line contains a recording station name, the year, month, day, maximum temperature, minimum temperature, and optionally, evaporation rate, and wind speed. If no data are available for any of these items on a given date, then an asterisk should be entered as its value.

When a climate file has days with missing values, SWMM will use the value from the most recent previous day with a recorded value.

For a user-prepared climate file, the data must be in the same units as the model being analyzed. For US units, temperature is in degrees F, evaporation is in inches/day, and wind speed is in miles/hour. For metric units, temperature is in degrees C, evaporation is in mm/day, and wind speed is in km/hour.