Degree Days are a practical method for determining cumulative temperatures over the course of a season. Originally designed to evaluate energy demand and consumption, degree days are based on how far the average temperature departs from a human comfort level of 19 °C *. Simply put, each degree of temperature above 19 °C is counted as one Cooling Degree Day, and each degree of temperature below 19 °C is counted as one Heating Degree Day. For example, a day with an average temperature of 25 °C will have 6 cooling degree days.
Also known as the "heat summation method." A scale created by the University of California at Davis in the 1930s to determine the suitability for vineyards in any given climate. Modern instrumentation has largely supplanted this scale. The total accumulative number of degrees above 50F during the growing season. If the temperature for any given day rises to 70F that day would add 20 points to the summation. Over the 200 days of the California growing season the total would range from less than 2,500 degrees days for the coolest areas, classified as Region I, to region V with more than 4,000 degree days.
A measure of how cold (or hot) the weather has been (relative to a stated base temperature) measured over a regular monitoring interval, usually weekly or monthly.
a measure of physiological time; it is a function of the temperature between and upper and lower threshold for growth (of a plant or insect) and the number of days that the temperature occurs between these thresholds.
A system by which heating oil dealers measure and record the daily temperature. This information is compared to what they know about your heating system to ensure automatic delivery before your system uses all of the oil in the storage tank.
Degree days are determined by subtracting average daily temperature from 65° F. Example: average daily temperature is 25° F, (65 – 25 = 40) then we have accumulated 40 degree days on this date.
number of degrees above a minimum temperature acceptable for growth, multiplied by time in days.
The degree-day figure for the year is the sum of all degree days of the year. The degree-day figure for a day is calculated as 17 degrees centigrade less the mean temperature of the day if less than or equivalent to 17 degrees centigrade. Otherwise the degree-day figure is 0.
A measure of the severity of a heating period, usually an entire season, based on climatic conditions. It is found by determining from weather records for each day the difference between 65 degrees F and the mean temperature for that day. The sum of these differences for all the days in the heating season is the Degree Days for that locality.
The absolute difference between the outdoor mean temperature and a base temperature over a 24-hour period (typically 65°F) (18.3°C). (For example, a mean temperature of 30°F (1.1°C) yields 35 (19.4) heating degree days; a mean temperature of 90°F (32.2°C) yields 25 (13.9) cooling degree days.) Degree days are roughly proportional to the weather loading on a structure.
Computed from each day's mean temperature (max+min/2). For each degree that a day's mean temperature is below or above a reference temperature is counted as one degree day.
The difference between a reference temperature (usually 65? F, 18.3? C) and the mean temperature for the day, times 24 hours, times the number of days in the period. Degree days are used to compare the severity of cold or heat during the heating or cooling season.
A measure of the coldness of weather to determine heating requirements. Degree days for a 24-hour period are calculated by adding the day's high and low temperatures and dividing by two, and subtracting the result from a reference point, usually 65 degrees Fahrenheit
The difference in temperature between 65 degrees fahrenheit and the average temperature over the previous 24 hour period. In example, if the average temperature over the previous 24 hour period was 30 degrees, 35 degree-days have elapsed.