Victoria Peak Weather Station [????- ]
Zooming in the photo of 1920s Houses at the Peak reveals the following:
I would suggest that the structure on the top of the hill on the left of the above zoom-in is Belvedere while the structure on the top of the hill on the right of the above zoom-in is the weather station, with the Eyrie in the valley in the middle. The post on 1890s Austin Arms Hotel also reveals this scene.
Indeed hfsiu had asked the question about the buildings and structures at the peak here, and annelisec's advice agrees with my observation, except that the structure labelled as '8' was not addressed. I believe that '8' is the weather station shown above. We can also see that annelisec's photo The Very Top of "The Peak" c.1880 also reveals this structure just overlooking the "Signalman's House" and of course the signal station and flagstaff further to the right. The following zoom-in of the 1920s Houses at the Peak also reveals this scene.
I have not yet been able to locate the exact year of the establishment of the weather station at the peak, but the first report of the Director of the Hong Kong Observatory Dr William Doberck dated November 1883 already mentioned the station at the peak: "His Excellency the Governor has already offered Sir Robert Hart the co-operation of the Hongkong Observatory, which is, owing to its (in meteorological aspects) un-equalled situation, its connection with a high level station on Victoria Peak, ...". In his report for the year 1884, he also mentioned "At Victoria Peak observations of the barometer, dry and damp bulb thermometers, direction and force of the wind, clouds, sea and state of the weather are made at 7 a. 10 a. 4 p. 7 p. and 10 p... The rainfall is collected in two gauges. One of them is an old roof-gauge. The other is placed one foot above the ground." So it is rather clear that the weather station had already existed before 1883.
Further views and suggestions are very much welcome!