Alpine shrub plants often show pronounced interannual variability in fruit production, yet the timing and form of temperature associations remain difficult to constrain in heavy-snow mountain systems. Using a long-term monitoring dataset for eight fruiting shrub species at Mt. Tateyama (Japan)—Empetrum nigrum var. japonicum, Vaccinium vitis-idaea, Gaultheria pyroloides, Vaccinium shikokianum, Sorbus matsumurana, Rubus vernus, Sorbus sambucifolia, and Pinus pumila—we aligned annual fruit production to Agricultural Years and evaluated temperature–production relationships with three complementary approaches. We combined Spearman rank correlations across a broad suite of temperature indices with false-discovery-rate screening, a daily-temperature sliding-window scan that compared candidate window lengths while controlling for lag-1 fruit production, and an AICc-based model comparison that contrasted gradual (linear/quadratic) responses with step-type threshold relationships for both focal-year and preceding-year (Pre-) temperature windows. Across methods, detectable signals were concentrated in a subset of species and time periods rather than being community-wide. Sliding-window results further indicated strong interspecific heterogeneity in the optimal window length, the most informative temperature predictor, and the timing of peak associations, with some taxa showing stronger support for Pre-year windows consistent with carry-over patterns. Threshold comparisons frequently favored step-type relationships, and significant cases were typically characterized by lower fruit-production residuals above the estimated temperature threshold. Together, these results highlight species- and period-specific temperature associations, motivating targeted mechanistic measurements and broader spatial replication to assess the robustness and drivers of carry-over and nonlinear responses. By helping identify species-specific sensitive temperature windows and potential nonlinearities, these patterns may inform expectations for how climate variability and warming could reshape the timing and magnitude of fruit resource pulses in alpine ecosystems. Such shifts could, in turn, influence consumer food availability and plant–animal interactions.