[Objectives]  To clarify the cold hardiness and overwintering ability of Spodoptera frugiperda and thereby predict its overwintering and year-round ranges in Fujian. [Methods]  The ability of S. frugiperda to survive low temperatures was analyzed using corrected mortality data and the species’ cold hardiness evaluated using LT₅₀, LT₉₀ and LT₉₉ values calculated by probability value analysis. Overwintering ability and regions of year-round occurrence were analyzed based on simulated overwintering with meteorological data, data on the number of pupae in soil, sex attractant trap capture results and the crop damage rate in fields. [Results]  Low temperature had significant lethal effects on various life stages of S. frugiperda. At temperatures of 0, 4 and 8 ℃, mortality increased with decreasing temperature and exposure time. The duration of survival to the LT₅₀, LT₉₀ and LT₉₉ treatments also decreased, regardless of the developmental stage. The ability of S. frugiperda to survive low temperatures varied greatly with temperature and developmental stage. Eggs and pupae had the lowest, and highest, cold hardiness, respectively. Among larval instars, the 1st to 3rd instars had greater cold hardiness than the 4th to 6th, and adult females had greater cold hardiness than adult males. Eggs should not survive between January and March in Minhou and Jin’an (Fuzhou). With respect to the winter viability of pupae in “no winter” maize regions, some pupae should successfully overwinter while others die gradually in Minhou (Fuzhou), Datian (Sanming) and Jian'ou (Nanping). However, adults that emerge in winter shouldn’t be able to reproduce due to the low temperature and absence of prefered host plants. Only 2.08% of pupae survived beyond March 15th and completed overwintering in Jin’an (Fuzhou). Young larvae, pupae and adults occur in maize fields in January and February, the coldest months of the year, in Xianyou (Putian) and Changtai (Zhangzhou), the two winter maize planting regions in Fujian province. [Conclusion]  Among the developmental stages of S. frugiperda, eggs and pupae have the lowest, and highest, cold hardiness, respectively. The pupa is therefore the most likely stage to overwinter in “no winter” maize regions. The regions where S. frugiperda is likely to overwinter and occur year-round are determined by the ambient temperature between January and March. Pupae can’t complete the entire overwintering process in regions where the average daily temperature is ≤12.6 ℃ between January and March, but can do so in regions where the average daily temperature is ≥14.2 ℃. S. frugiperda can damage maize crops year round in winter maize planting regions where the average daily temperature is ≥15.0 ℃ between January and March, and can overwinter as young larvae, pupae and adults in these regions.