Flooding is a significant threat to life and property in Hawaiʻi. As climate warming continues to alter precipitation patterns and hydrological processes in the tropics, characterizing the shifting patterns in magnitude, seasonality, and location of floods would improve our understanding of the consequences and better prepare us for future flood events. In this study, 84 rain gauges and 111 crest gauges across five major Hawaiian Islands were analyzed from 1970 to 2005. We estimated trends in the annual maximum daily rainfall (RF_max) and the annual peak flow (PF_max) using the Mann-Kendall test and Senʻs slope. Subsequently, we examined the association between PF_max and rainfall. Then, we assessed temporal shifting by combining circular analysis with Senʻs slope. The main identified trends showed decreases in RF_max and PF_max (67% and 61% of all gauges, respectively). The physiography of the Hawaiian islands (i.e., windward vs. leeward) has little contribution to both trends. In addition, PF_max trend cannot be fully attributed to RF_max trend, and in many cases, RF_max and PF_max did not occur coincidently. We also found the timing of RF_max and PF_max occurred in early wet season during the El Niño years and shifted even earlier from 1970 to 2005, likely due to the change of El Niño. These findings have implications for assessing flood risk. Our finding will aid watershed management and flood mitigation, and can increase resilience of downstream communities and near-shore environments.

洪水对夏威夷的生命和财产构成重大威胁。随着气候变暖继续改变热带地区的降水模式和水文过程，表征洪水规模、季节性和位置的变化模式将提高我们对后果的理解，并更好地为未来的洪水事件做好准备。在这项研究中，从 1970 年到 2005 年，对夏威夷五个主要岛屿的 84 个雨量计和 111 个波峰计进行了分析。我们使用 Mann-Kendall估计了年度最大日降雨量 (RF _max ) 和年度峰值流量 (PF _max ) 的趋势测试和 Sen's 斜率。随后，我们检查了 PF _max之间的关联和降雨。然后，我们通过将循环分析与 Sen's 斜率相结合来评估时间偏移。主要确定的趋势显示 RF _max和 PF _max 下降（分别为所有仪表的 67% 和 61%）。夏威夷群岛的地貌（即迎风与背风）对这两种趋势几乎没有影响。此外，PF _max趋势不能完全归因于RF _max 趋势，并且在许多情况下，RF _max和 PF _max并非同时发生。我们还发现了 RF _max和 PF _max的时序发生在厄尔尼诺年的早期雨季，从 1970 年到 2005 年转移得更早，可能是由于厄尔尼诺现象的变化。这些发现对评估洪水风险具有重要意义。我们的发现将有助于流域管理和减轻洪水，并可以提高下游社区和近岸环境的复原力。