The temperature of external air is now reduced to 15-20 degrees from the normal 25-34 degrees and is humidity reduced to 50-60% RH from the normal 70% RH, there are about resulted in a clean room humidity decreases below the standard value. The weather this does not happen often. Anticipated date range 25- 27 Jan, 2016 (according to the meteorological department). When the external air temperature and humidity into the normal State would cause the humidity in clean room according to the standard value.