Recently, abnormally cold winters and hot summers have generated interest in the duration of time that design temperature values have been equaled or exceeded. ETAC's Engineering Meteorology Section did a pilot study to examine temperature records for several military installations and give some insight into durations that may occur. We chose sites to represent different climatic regimes. For each site, we generated statistics on the number of occurrences of durations of one, two, three, . . . up to eight hours for each of the design temperature values (1%, 2½%, and 5% temperatures for the summer months; 99% and 97½% for winter months). We also made a study of the longest duration for each design value. We used the latest available 15 consecutive years of temperature data for all sites. We also made a comparison of data for the 15-year period of record (POR) versus data for the total available POR for some of the sites. Results were inconclusive and indicate that more study is needed.

Units: I-P