Yesterday's Weather and Radiation Level

Bulletin issued at 00:15 HKT 23/Oct/2025

HKO Readings & Radiation level

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

Hong Kong Observatory
Maximum Air Temperature                     20.9 C
Minimum Air Temperature                     18.2 C
Grass Minimum Temperature                   18.9 C
Relative Humidity                        67 - 85 Percent
Rainfall                                     3.3 mm 
Total rainfall since 1st January          2544.7 mm
Against an average of                     2356.5 mm

Other Stations                Min                  Max
King's Park                  17.4 C               19.8 C
Wong Chuk Hang               18.6 C               21.4 C
Ta Kwu Ling                  16.2 C               19.1 C
Lau Fau Shan                 16.4 C               19.7 C
Tai Po                       17.0 C               19.9 C
Sha Tin                      17.2 C               20.1 C
Tuen Mun                     17.0 C               20.1 C
Tseung Kwan O                17.0 C               19.4 C
Sai Kung                     17.8 C               20.1 C
Cheung Chau                  17.2 C               19.3 C
Chek Lap Kok                 17.9 C               21.2 C
Tsing Yi                     17.6 C               20.7 C
Tsuen Wan Ho Koon            15.5 C               18.3 C
Tsuen Wan Shing Mun Valley   17.0 C               20.3 C
Hong Kong Park               18.1 C               20.9 C
Shau Kei Wan                 17.9 C               20.1 C
Kowloon City                 17.1 C               19.3 C
Happy Valley                 19.0 C               21.9 C
Wong Tai Sin                 17.7 C               20.2 C
Stanley                      18.6 C               20.7 C
Kwun Tong                    17.4 C               20.1 C
Sham Shui Po                 17.6 C               20.2 C
Kai Tak Runway Park          18.6 C               21.4 C
Yuen Long Park               16.9 C               20.0 C
Tai Mei Tuk                  16.3 C               19.6 C

Duration of sunshine (King's Park):              0 H
The mean UV index recorded at King's Park yesterday was 1,
the UV intensity was LOW.
The maximum UV index for yesterday was 3.

Yesterday's (22 Oct 2025) average ambient gamma radiation
dose rate taken outdoors in Hong Kong ranged from 0.08 to
0.15 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                           0.08
Tap Mun                             0.09
Kat O                               0.10
Yuen Ng Fan                         0.12
Tai Mei Tuk                         0.12
Sha Tau Kok                         0.10
Kwun Tong                           0.13
Sai Wan Ho                          0.09
King's Park                         0.15
Tsim Bei Tsui                       0.13
Cape D'Aguilar                      0.13
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.