Because of the complexities of their flowering parameters, it is difficult to make generalizations about flowering phenology among temperate angiosperms. We examined patterns of flowering time and duration among 2867 Korean angiosperm species, and these patterns were associated with climatic factors. The effect of taxonomic membership was also tested. Overall data pooled over species from 165 families showed that 63.8% of these angiosperms flowered in summer, 19.5% in spring, 16.5% in autumn, and 0.2% in winter. Summer and autumn flowering periods were significantly longer than springtime events. Both mean monthly temperature and precipitation were strongly positively correlated with the number of species in flower, but not with flowering duration. The seven largest families differed in their flowering season and duration; both parameters were also segregated among genera within large families. In a two-way analysis, both flowering season and family membership exerted significant effects on flowering duration. These results demonstrate that the evolutionary influence on flowering time and duration can be observed at the community level when two factors are considered, i.e., the interaction of flowering parameters and the taxonomic composition of species within those communities.