This is the time of year when the weather is affected by cold high-pressure areas from the continent. These create sharp differences in temperature, generating strong upward currents. Also, humidity is low, and there is less concern about rain caused by hot air currents running into cold air at high altitudes.
因為此時天氣受大陸冷高壓的影響，晝夜溫差大、對流強，就有旺盛的上升氣流；而空氣濕度小，不必擔心熱氣流在高空遇冷會凝結成雲下雨。