The weather will not affect the scheduled launch of Shenzhou VII tonight, said weather experts, although the Jiuquan Satellite Launch Center has been bathed in drizzle since the morning of September 20.

The rain pattern is not normal according to weather records of the same period in the past few years, but the weather forecast indicates that it will have no impact on the spaceship launch, said a weather expert in the launch center's meteorological service.

Good weather conditions through launch window

Weather conditions are important for the successful launch of Shenzhou VII. Wind, thunder and temperature are the most influential elements. According to the weather forecast, during the period when the launch window will be open – between 9:07 PM to 10:27 PM (Beijing Time) -- wind speed should be below 8 meters per second at low altitude and 5 to 7 meters per second at ground level. In spite of some mist there is no likelihood of thunder, and the temperature will be around 15° Celsius. The sky will be dust-free with a visibility of 25 kilometers. All the statistics indicate that good weather conditions will accompany the spaceship launch, said Qiao Lin, chief forecaster of China's Meteorological Administration.

An unforgettable moment: abrupt weather change before Shenzhou VI launch

The launch window of Shenzhou VI was set at 9 AM on October 12, 2005 (Beijing Time). A cold front was expected to hit the launch center two days before the scheduled time. Strong winds and snowfall accompanied the cold air. It left Qiao Lin, at the time director of the Weather Service team, scratching his head. "We had to make a judgment call almost at the wire as to whether the snow and wind would stop in time for the launch. You can imagine the pressure," recalled Qiao.

The final analysis showed the snow would stop and the wind slow down four hours before the scheduled launch. A successful blast-off confirmed the forecast. "Although forecasts can't be made with one hundred percent precision, we as weathermen must collect experience from daily forecasts and meet the challenge of critical situations to prepare ourselves for future missions," said Qiao.

(China.org.cn by Huang Shan, September 25, 2008)