Biological processes at low latitudes are often associated with seasonal rainfall, while those at high altitudes are also influenced by low temperature and high humidity. Thus, the breeding phenology of montane species at low latitudes requires clarification. We monitored the timing of nesting for two species of secondary cavity-nesting passerine, the Green-backed Tit (Parus monticolus) and the Rufous-faced Warbler (Abroscopus albogularis), in a montane cloud forest in subtropical Taiwan between 2010 and 2014. To determine the effects of weather and extreme events on nesting success, we used program MARK to model daily nest survival rate as a function of weather variables. The results showed that March temperatures, but not spring (February–March) rainfall, affected the mean laying date of Green-backed Tits. Females shifted their laying dates to lay earlier in response to earlier warm spring weather. The Rufous-faced Warbler exhibited a similar but weaker relationship between March temperature and mean laying date. Spring temperature and rainfall did not affect the length of the laying season of either species. The reduction in the limiting effect of spring rainfall on biological processes may be attributable to the perhumid climate of the study area. Both species were negatively affected by heavy seasonal rainfall during the nesting period. Nest survival declined under extremely heavy rainfall (daily precipitation >20 mm), but did not vary linearly or nonlinearly with daily precipitation levels. The daily survival rate of Green-backed Tits was further reduced by cold weather combined with heavy rain. Our results show that the breeding densities of both species declined across the 5-yr study period, indicating that the negative effects of adverse weather may contribute to further decreases in annual productivity, which would accelerate population declines at the current rate of climate change.