Ants and mosquitoes can ruin a good picnic, but that's nothing compared to what a vigorous storm can do to a weekend at the beach. Before you leave for that dream vacation, check out these Web sites to see what kind of weather you will encounter:

• AccuWeather: While you are deciding whether to pack a sweater or a t-shirt, sunblock or an umbrella, pay a visit to AccuWeather. By entering a city or zip code, you can find out what meteorologists think the weather will be for the coming week at your destination. You can also choose a state and watch a satellite animation showing changes in the weather.
• National Oceanic and Atmospheric Administration: From this Web site, you can get long-term forecasts, eight days in advance.
• USA Today Online Weather Almanac: For travel planning, this site offers monthly climate data for cities the world over. Go here to find out what the average monthly high and low temperatures, rainfall, and snowfall are in a vacation spot that you are eyeing.