and Northern Sydney, the Eastern Suburbs Banksia Scrub in the coastline and the Blue Gum High Forest which is scantily present in the North Shore – All of which are critically endangered. The city also includes the Sydney Sandstone Ridgetop Woodland found in Ku-ring-gai Chase National Park on the Hornsby Plateau to the north. Sydney is home to dozens of bird species, which commonly include the Australian raven, Australian magpie, crested pigeon, noisy miner and the pied currawong, among others. Introduced bird species ubiquitously found in Sydney are the common myna, common starling, house sparrow and the spotted dove. Reptile species are also numerous and predominantly include skinks. Sydney has a few mammal and spider species, such as the grey-headed flying fox and the Sydney funnel-web, respectively, and has a huge diversity of marine species inhabiting its harbour and many beaches. Climate Under the Köppen–Geiger classification, Sydney has a humid subtropical climate (Cfa) with "warm [and] sometimes hot" summers and "cool" winters, as described by the Australian Bureau of Statistics. The El Niño–Southern Oscillation, the Indian Ocean Dipole and the Southern Annular Mode play an important role in determining Sydney's weather patterns: drought and bushfire on the one hand, and storms and flooding on the other, associated with the opposite phases of the oscillation in Australia. The weather is moderated by proximity to the ocean, and more extreme temperatures are recorded in the inland western suburbs. At Sydney's primary weather station at Observatory Hill, extreme temperatures have ranged from on 18 January 2013 to on 22 June 1932. An average of 14.9 days a year have temperatures at or above in the central business district (CBD). In contrast, the metropolitan area averages between 35 and 65 days, depending on the suburb. The hottest day in the Sydney metropolitan area occurred in Penrith on 4 January 2020, where a high of was recorded. The average annual temperature of the sea ranges from in September to in February. Sydney has an average of 7.2 hours of sunshine per day and 109.5 clear days annually. Due to the inland location, frost is recorded early in the morning in Western Sydney a few times in winter. Autumn and spring are the transitional seasons, with spring showing a larger temperature variation than autumn. Sydney experiences an urban heat island effect. This makes certain parts of the city more vulnerable to extreme heat, including coastal suburbs.