Yesterday's Weather and Radiation Level

Bulletin issued at 00:15 HKT 18/Dec/2025

HKO Readings & Radiation level

Yesterday's Weather and Radiation Level:
------------------------------------------------------

Hong Kong Observatory
Maximum Air Temperature                     25.3 C
Minimum Air Temperature                     18.3 C
Grass Minimum Temperature                   14.2 C
Relative Humidity                        52 - 83 Percent
Rainfall                                       0 mm 
Total rainfall since 1st January          2556.4 mm
Against an average of                     2419.5 mm

Other Stations                Min                  Max
King's Park                  17.3 C               26.7 C
Wong Chuk Hang               14.5 C               27.9 C
Ta Kwu Ling                  11.8 C               28.6 C
Lau Fau Shan                 15.9 C               29.1 C
Tai Po                       15.1 C               25.7 C
Sha Tin                      13.8 C               26.5 C
Tuen Mun                     16.7 C               28.2 C
Tseung Kwan O                14.7 C               26.3 C
Sai Kung                     15.9 C               23.7 C
Cheung Chau                  16.9 C               26.8 C
Chek Lap Kok                 17.5 C               26.3 C
Tsing Yi                     15.8 C               28.0 C
Shek Kong                    13.3 C               28.0 C
Tsuen Wan Ho Koon            15.1 C               27.3 C
Tsuen Wan Shing Mun Valley   14.6 C               28.2 C
Hong Kong Park               17.1 C               26.6 C
Shau Kei Wan                 17.4 C               24.2 C
Kowloon City                 16.9 C               28.2 C
Happy Valley                 14.8 C               27.7 C
Kwun Tong                    16.5 C               26.2 C
Sham Shui Po                 16.8 C               28.3 C
Kai Tak Runway Park          17.8 C               25.3 C
Yuen Long Park               14.4 C               29.2 C
Tai Mei Tuk                  16.3 C               25.3 C

Duration of sunshine (King's Park):9.5 H    
The mean UV index recorded at King's Park yesterday was 2the UV intensity was LOW 
The maximum UV index for yesterday was 5.

Yesterday's (17 Dec 2025) average ambient gamma radiation
dose rate taken outdoors in Hong Kong ranged from 0.09 to
0.16 microsievert per hour.  These are within the normal
range of fluctuation of the background radiation level in
Hong Kong (See Note). The average dose rates measured at the
radiation monitoring stations over various parts of the
territory were as follows :

Station                     Yesterday's average
                            (microsievert/hour)
Ping Chau                           0.09
Tap Mun                             0.09
Kat O                               0.10
Yuen Ng Fan                         0.12
Tai Mei Tuk                         0.12
Sha Tau Kok                         0.11
Kwun Tong                           0.13
Sai Wan Ho                          0.09
King's Park                         0.16
Tsim Bei Tsui                       0.14
Cape D'Aguilar                      0.14
Chek Lap Kok                        0.15   


Note
1.     From readings taken at various locations in Hong Kong in the
       past, the hourly mean ambient gamma radiation dose rate may
       vary between 0.06 and 0.3 microsievert per hour. (1
       microsievert = 0.000001 sievert = 0.001 millisievert)

2.     Temporal variations are generally caused by changes in
       meteorological conditions such as rainfall, wind and
       barometric pressure.

3.     Spatial variations are generally caused by differences in
       the radioactive content of local rock and soil.

4.     The data displayed is provisional. Only limited data
       validation has been carried out.

5.     The range of relative humidity in the daily weather summary
       originates from the observer's reports of Hourly
       Readings of the day. This follows the long-term practice of
       collecting climatological data of the Hong Kong Observatory
       for over a century. It may differ from the relative humidity
       range derived from the 1-minute reports of the automatic
       weather station.