In Beijing, the capital of China, located in the northeast of the country, 140 km (85 mi) away from the Bohai Sea coast, the climate is continental, with cold but sunny winters, and hot, sultry and rainy summers. Like many areas of China, the city is affected by the monsoon circulation: in winter the northwest cold currents will prevail, while in summer they will be replaced by hot and humid currents of tropical origin. Spring and autumn are transitional periods.
Here are the average temperatures.
Beijing - Average temperatures
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)-8-608141922211580-6
Max (°C)251220263031302619104
Min (°F)182132465766727059463221
Max (°F)364154687986888679665039

Precipitation amounts to 570 mm (23 inches) per year: the rains are not abundant, but are concentrated in the summer months. Here is the average precipitation.
Beijing - Average precipitation
MonthJanFebMarAprMayJunJulAugSepOctNovDecYear
Prec.(mm)3610253070175180502062578
Prec.(in)0.10.20.411.22.86.97.120.80.20.122.8
Days2345691412753272

In winter, the average temperature is a few degrees below freezing (0 °C or 32 °F); sunshine is quite common, and a cold wind blows from the deserts of Mongolia. On colder periods, the temperature remains below freezing during the day as well, and at night it can drop to -15/-18 °C (0/5 °F). Although the winter is a dry season, sometimes it can snow.
In winter and especially in spring (March to May), the city can be affected by the yellow dust, coming from the deserts of Mongolia and Central Asia, which forms a characteristic haze and brings breathing problems and eye irritation. On the other hand, when the wind is weak and the air is stagnant (a situation that occurs more easily in winter, while in summer the heat usually causes rising currents, besides it can rain), the city can be hit by smog.

In spring, the temperature increases rapidly, so much so that already in April it often exceeds 20 °C (68 °F), and in May the average maximum around 26 °C (79 °F) confirms the precocity of the warm weather.

In June, it's already as hot as in the middle of summer, in fact in July and August the maximum temperature does not increase any more. This happens because around mid-June the summer monsoon arrives, bringing rains, sometimes heavy, and high humidity. So, in Beijing summer is hot, but especially muggy. July and August are the rainiest month. Anyway, even in summer there may be entire weeks without rain, and these periods are usually the hottest ones, with highs about 35 °C (95 °F), and with the perceived temperature exceeding 40 °C (104 °F) because of the humidity. In July 2015, the real temperature reached 40 °C (104 °F). The monsoon is quite irregular, here as well as in the north-eastern part of China, so the rains may be more or less abundant depending on the year.
To escape the summer heat, locals go to Beidaihe or generally along the coast of the Bohai Sea, where sea breezes temper the heat.

In autumn, the weather improves, rainfall decreases, and by October the rains are quite rare. By September, the humidity decreases and the weather becomes pleasant, while in October the nights begin to be very cool.

Beijing

The sun in Beijing shines quite often all year round, for a total of 2,650 hours. The least sunny months, at least in comparison to the length of the days, are July and August.
Beijing - Sunshine
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Hours677899778766

Near Beijing, the sea is very cold in winter, but it warms up a lot in summer, reaching 25 °C (77 °F) in August.
Beidaihe - Sea temperature
MonthJanFebMarAprMayJunJulAugSepOctNovDec
Temp (°C)4347121823252319148
Temp (°F)393739455464737773665746

From July to early October (and occasionally also in the second half of June), Beijing can be affected by typhoons, the tropical cyclones of South-East Asia, although this area of China is less exposed than the south.

When to go


In order to avoid both the cold in winter and the heat and the rains in summer, the best times to visit Beijing are spring and autumn, and in particular from mid-April to mid-May and from mid-September to mid-October.