Været i Shenzhen i september

December in Shenzhen is the mild, dry end of the Pearl River Delta year. Regulars give nights of 8 to 10C and days of 15 to 20C - our row runs a little warmer at 13C and 21.3C - and the clothing consensus is a scarf and something over your shoulders for the evening rather than a coat, with layers doing the work; their line is that two t-shirts beat one. It is also among the driest months here, 14mm across 2.9 days. The figure our row adds and the forum does not discuss is AQI 112, the winter haze that settles over the delta once the summer rain stops. The record: feels-like 21C by day and 11C at night, humidity 66 percent, 8 hours of sun and a 19.3C sea.

Shenzhen forum threads describe the transition out of winter into spring as one of the more pleasant stretches of the year, with posters recommending light layers - a polo shirt or long-sleeve top plus a thin jacket for cooler mornings and evenings, and something extra for heavily air-conditioned indoor spaces. Posters flagged occasional rain and afternoon thunderstorms, typically rolling through around 3-4pm, as a normal feature even in the milder shoulder-season stretch. The consistent advice was to bring a thin coat or cardigan that can layer on or off through the day, since the temperature swing between an early morning and a warm afternoon can be considerable this time of year.

Shenzhen forum regulars, drawing on the same climate conversation as nearby Guangzhou and Hong Kong, describe July as hot, very humid and very wet, arriving right alongside typhoon season with risk building toward month's end. The standard workaround: outdoor plans before 11am and after 5pm, midday hours in air-conditioned museums, cafés or malls — the same schedule regulars recommend across the whole Pearl River Delta region this time of year. Summer holidays bring larger crowds on top of the weather, so hotels and attractions run busier than the conditions alone might suggest. Our record: 31.5°C days, 84.3% humidity and 19.6 rain days — hot, humid and wet nearly two-thirds of the month, matching the “not ideal, plan around it” read the regional forums give July.

The Guangzhou-Shenzhen forum describes January as cool by regional standards rather than genuinely cold — overnight lows down near 8–10°C, daytime highs back up in the high teens, with a scarf and light coat enough for evenings out. Regulars call it one or two thin layers, not full winter gear, even in the coolest stretch of the year.