Climate:

subtropical region, Sindh is hot in the summer and cold in winter. Temperatures frequently rise above 46 °C (115 °F) between May and August, and the minimum average temperature of 2 °C (36 °F) occurs during December and January. The annual rainfall averages about seven inches, falling mainly during July and August. The southwest monsoon wind begins to blow in mid-February and continues until the end of September, whereas the cool northerly wind blows during the winter months from October to January.
Highest and lowest temperatures
The highest temperature throughout Pakistan are usually recorded in - Shaheed Benazeerabad District (Previously called Nawabshah District) and Sibbi from May to August each year which rises to above 48 degree centigrade. The climate is dry and hot but sometimes falls to 0 degrees Celsius and falls to lower than minus seven in December or January once in a quarter of the century.
Sindh lies between the two monsoons - the southwest monsoon from the Indian Ocean and the northeast or retreating monsoon, deflected towards it by Himalayan mountains — and escapes the influence of both. The average rainfall in Sindh is only 15 to 18 cm per year, but the loss during the two seasons is compensated by the Indus, in the form of inundation, caused twice a year by the spring and summer melting of Himalayan snow and by rainfall in the monsoon season. These natural patterns have changed somewhat with the construction of dams and barrages on the Indus.
Climatically, Sindh is divided in three sections - Siro (upper section centred on Jacobabad), Wicholo (middle section centred on Hyderabad), and Lar (lower section centred on Karachi). In Upper Sindh,[2] the thermal equator passes through Sindh. The highest temperature ever recorded was 53 °C (127 °F) in 1919. The air is generally very dry. In winter frost is common.
In Central Sindh, average monsoon wind speed is 18 km/hour in June. The temperature is lower than Upper Sindh but higher than Lower Sindh. Dry hot days and cool nights are summer characteristics. Maximum temperature reaches 43-44 °C (110-112 °F). Lower Sindh has a damper and humid maritime climate affected by the south-western winds in summer and north-eastern winds in winter and with lower rainfall than Central Sindh. The maximum temperature reaches about 35-38 °C (95-100 °F). In the Kirthar range at 1,800 m7 and higher on the Gorakh Hill and other peaks in Dadu District, temperatures near freezing have been recorded and brief snow fall is received in winters.