Cell phone networks worldwide are on the brink of becoming sophisticated weather gauges. For years wireless networks have dealt with impeded signals during rain, snow, fog, or hail. The networks monitor their signals closely and strengthen them as necessary, to maintain a good signal for customers. As it turns out, this monitoring and subsequent adjusting provides weather information that may be even more precise than methods currently used by meteorologists, says Hagit Messer. Messer is vice president for research and development at Tel Aviv University in Israel. "The weather affects the signal strength dramatically," she said. If better real-time weather data can be collected, weather prediction will improve, she says. Messer and her team tested the accuracy of cell phone weather data last year and were impressed enough with the results that they have filed a preliminary patent application for the process. The degree of signal interference, called attenuation, depends on the size and distribution of the rain droplets, according to the Israeli team, whose paper has been published in the journal Science. In an experiment during a rainstorm in January 2005, the team collected data every 15 minutes from cell phone networks about signal-strength adjustments.