The length of the vectors on our wind rose graph show the percentage of time the wind blew from each direction. Wind speed, pollutant concentration or temperature is delineated by color and width of the brackets.

• Use the calendar controls or manually enter the Start Date and End Date for the data set in the format mm/dd/yyyy. The end date must be later than the start date, and no dates earlier than 1/1/1990 will be accepted. Any date entry problems requiring action are described beneath the input fields.

• The Parameter and Station lists refresh automatically according to data available for the selected dates.

• After selecting the desired parameter and station, click Display to generate the wind rose.