## 1 Introduction  
Extreme weather events, especially extreme temperatures, are natural disasters that significantly impact human life and society [1, 2, 3, 4, 5]. These extreme events have negative effects on humans and society, including loss of life [6], increased financial risk in the energy sector [7], and substantial impacts on crop growth [8] and health of newborns [9]. Evidence suggests that anthropogenic global warming has increased the probability of extreme events such as heat waves and cold spells, droughts, floods, and tropical cyclones [10, 11, 12, 13, 14, 15, 16].  
The quasi-biweekly oscillation (QBWO) and intraseasonal oscillation (ISO) play a predominant role in influencing extreme weathers in East Asia [17, 18, 19, 20, 21]. For example, the QBWO and boreal summer ISO (BSISO) modulate the probability of extreme temperature events that coincide with extreme precipitation events over the South China and Southeast China regions, including the Guangdong-Hong Kong-Macau Greater Bay Area [20]. It is also reported that extreme heat waves can be induced by 5-25- and 30-90-day oscillations associated with anomalous cyclones in the tropical western Pacific [22].  
Despite numerous studies on the QBWO and ISO in South China and Hong Kong, there has been limited attention paid to quasi-biweekly to intraseasonal extreme (QBIE) temperature events in this region. Most research on temperature extremes has focused on the synoptic timescale rather than on the biweekly and intraseasonal timescales [23, 24, 25]. However, temperature extremes are also observed on these timescales. For example, [PERSON] et al. [26] documented that ISOs increase the mean temperature by 1.93 degrees Celsius during compound drought and heat events in the Yangtze River basin. Additional direct evidence is the long-duration heat wave that occurred in July 2023, during which Hong Kong recorded 19 consecutive days with daily maximum air temperatures exceeding 33 \({}^{\circ}\)C. During this long-lived heat event, the maximum air temperature reached 36.1 \({}^{\circ}\)C on 27 July 2023, setting a new record for July that was also approximately 1.5 \({}^{\circ}\)C higher than pre-industrial averages. Thus, it is of great importance to study temperature extremes in the QBWO and ISO timescales.  
Due to the lower degree of freedom of the intraseasonal signals, long historical data can help reduce the uncertainty in analysis results. However, the study periods of most publications were limited to recent decades due to limited data records. Aimed at addressing this gap, this study constructed a century-long QBIE temperature extreme dataset based on meteorological station records in Hong Kong dating back to 1885. This study thoroughly investigates the climatology, diversity, long-term variability, and predictability of QBIE events in the past century, with a particular focus on QBIE temperature events. The remaining of this paper is organized as follow: Section 2 introduces the data employed in this study, Section 3 explains how we define and identify the historical QBIE temperature events, Section 4 examines the climatology and diversity of these extreme events, Section 5 discusses the long-term variability and predictability of QBIE temperature events in the past decades, and finally, conclusions and discussion are given in Section 6.