Shiraz’s climate has distinct seasons, and is overall classed as a hot semi-arid climate (Köppen: BSh), though it is only a little short of a hot-summer Mediterranean climate (Csa).
Summers are hot, with a July average high of 37.8 °C (100.0 °F). Winters are cool, with average low temperatures below freezing in December and January. Around 300 mm (12 in) of rain falls each year, almost entirely in the winter months, though in some cases as much as this has fallen in a single month (as in January 1965 and December 2004), whilst in the year from July 1965 to June 1966 as little as 82.9 millimetres (3.3 in) fell. The wettest year has been 1955/1956 with as much as 857.2 millimetres (33.75 in), though since 1959 the highest has been around 590 millimetres (23.2 in) in each of 1995/1996 and 2004/2005.
Shiraz contains a considerable number of gardens. Due to population growth in the city, many of these gardens may be lost to give way to new developments. Although some measures have been taken by the Municipality to preserve these gardens, many illegal developments still endanger them.
The highest record temperature was 43.2 °C (109.8 °F) on 21 July 1980 and the lowest record temperature was −16 °C (3 °F) on 25 December 2006.