The relationship between the population density of overwintering adults of the brown marmorated stink bug and the temperatures of each month during the preceding November to April was investigated in Akita Prefecture, northern Japan, from 1999 to 2012. The number of adults entering traps for overwintering at the monitored hibernation site differed considerably among years. There was a significant negative correlation between the increase ratio (the ratio of the number collected in the current year to the number collected in the previous year) and the mean daily maximum temperature of the preceding March and April. These results suggest that the proportion of surviving adult brown marmorated stink bug may be higher when temperatures in early spring (March and April) are lower, as the postoverwintering adults may need to survive without food for a shorter period of time.