After days of scorching heat, Shenzhen is seeing a welcome respite as a rainy spell arrives, expected to last through July 21. Local weather authorities said a northward-moving monsoon trough will bring frequent thunderstorms, gusty winds and downpours, keeping temperatures between 26 and 30 degrees Celsius. The rain coincides with the start of this year’s 40-day “sanfu” period — commonly known as the dog days of summer — which began yesterday and ends Aug. 23. The period typically brings high heat, high humidity and light winds to much of China, conditions often described as feeling like being “steamed and boiled”