DESPITE ITS SWAMPLIKE CHARACTERISTICS, Washington is not the most humid place in the world; it's not even the most humid city in the country during July and August. With an average daily maximum temperature of 87 degrees in July and 85.8 degrees in August, the relative humidity in D.C. during those months is 87 percent in the morning and 56 percent in the afternoon in July and 89 percent and 56 percent, respectively, in August. Compared with several other locations, Washington seems dry.

ST. PAUL ISLAND, ALASKA, is the most humid place in the country, with an average relative humidity of 96 percent in the morning and 90 percent in the afternoon in July and 95 percent in the morning and 90 percent in the afternoon during August. Of course, it's cool there; the average daily maximum temperature is only 45.3 degrees in July and 43.7 degrees in August. Perfect weather for seals.

The town you might want most to bypass on your summer vacation is PORT ARTHUR, TEX., famous as the home town of rock 'n' roll superstar Janis Joplin and infamous for its heat and humidity. The average daily maximum temperature during July is 92.5 degrees, and in August, 92.2 degrees. Between the heat and an average relative humidity of 94 percent in the morning and 66 percent in the afternoon in both July and August, you can guess why Joplin's style ran toward the steamy.

For the driest summer ever, there is LAS VEGAS. The average relative humidity in July is only 29 percent in the morning and 15 percent in the afternoon. In August, it's 35 percent and 17 percent, making it the least humid city in the nation. Vegas is hot -- the average daily maximum temperature is 104.5 degrees in July and 101.9 in August -- yet heat hardly matters. No one stays outside long enough to even comment on the weather; all the casinos are air-conditioned.