28 FEBRUARY 2003
DATA SET PAGE 10: ANNUAL TEMPERATURE SUMMARY. Figure 2-10
is an example of Data Set Page 10. This chart shows a week-by-week summary of dry
bulb temperatures for the given site. The observations are grouped into 7-day periods
(approximate calendar weeks). For example, observations from January 1 through 7
from all years are grouped, observations from January 8 through 14 from all years are
grouped, and so on, overlapping the end of one month and beginning of the next month
where necessary. The following statistics are shown for each of the 7-day periods:
1% Dry Bulb Temp is the dry bulb temperature that is exceeded 1% of the time
during that calendar week.
MCWB (1% Dry Bulb) is the mean of wet bulb temperatures coincident with 1%
dry bulb temperatures during the same week.
Mean Max Temp is the daily maximum dry bulb temperature, averaged by week
over the POR.
Mean Min Temp is the daily minimum dry bulb temperature, averaged by week
over the POR.
99% Min Dry Bulb Temp is the daily dry bulb temperature that is at or above this
value 99% of the time, or below this value 1% of the time.
NOTE: The information in this chart is calculated on a weekly basis; information on a
climate summary (Data Set Page 1) is calculated on an annual basis.
Suggestions for Use. The weekly 1% and 99% temperatures are useful for
understanding the probable temperature extremes that can occur during a given week
of the year. The weekly dry bulb temperatures are useful for understanding the change
of seasons at a given location. The display is helpful for mission planning and
construction project planning.
Designers. The values displayed here are based on the 30-year record. It
is important that designers not base equipment selection on the "highest" or "lowest"
recorded temperature at the station. That error would result in selecting equipment
extremely costly to install, which would operate inefficiently for all but the very hottest
or coldest single hour in 30 years. See the Design Criteria Data section on Sample
Data Set Page 1 (see Figure 2-1) in this document for appropriate maximum and
minimum temperatures for sizing equipment.
Construction and Operation Planners. The mean maximum and minimum
temperatures shown for each week seldom occur in the same year. Keep in mind that
these are mean values that are useful for understanding the typical range of
temperatures in a given week. The difference does not represent the actual day-night
temperature swing in a given week.