below ) in spring is 1 May and average date for first freeze in autumn is 9 October giving a frost-free season of 160 days (Trondheim Airport Værnes 1981-2010 average). The earliest weather stations were located closer to the city centre, from 1945 onwards the weather station has been located at a higher elevation (Voll, 127 m and Tyholt, 113 m), therefore being slightly colder. A new sunrecorder was established by met.no in the city at Gløshaugen (NTNU) December 2015, recording more sunhrs than earlier sunrecorder, which had terrain blocking issues. There are on average 229 sunhours in July (based 2016–2020). Trondheim recorded 197 sunhours in October 2016 beating the previous national record for October. In April 2019, Trondheim recorded 308 sunhours, setting a new national record for April. In contrast, December 2016 only recorded 10 sunhours. Fauna The city has various wetland habitats. among which there is the Gaulosen. The observation tower accommodates for birdwatching and providing information about birdlife. Despite Trondheim being Norway's third largest city, wild animals can be seen. Otters and beavers thrive in Nidelva and Bymarka. Badgers and red foxes are not uncommon sights. Moose and deer are common in the hills surrounding the city, and might wander into the city, especially in May when the one-year-olds are chased away by their mothers, or in late winter when food grows scarce in the snow-covered higher regions. From 2002 until 2017, a wolverine lived in Bymarka. Cityscape and sites Most of Trondheim city centre is scattered with small speciality shops. However, the main shopping area is concentrated around the pedestrianised streets Nordre gate (), Olav Tryggvasons gate and Thomas Angells gate even though the rest of the city centre is provided with everything from old, well-established companies to new, hip and trendy shops. In the mid-to-late 1990s, the area surrounding the old drydock and ship construction buildings of the defunct Trondhjems mekaniske Værksted shipbuilding company at the Nedre Elvehavn was renovated and old industrial buildings were torn down to make way for condominiums. A shopping centre was also built, known as Solsiden (The Sunny Side). This is a popular residential and shopping area, especially for young people. DORA 1 is a German submarine base that housed the 13th U-boat Flotilla during the Second World War occupation of Norway. Today the bunker houses various archives, among them the city archives, the university and state archives. More recently,