The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) poses a significant threat to global maize production, particularly in tropical and subtropical regions. It is an invasive and highly destructive insect. This study presents a quantitative assessment of the influence of varying maize planting dates on S. frugiperda, dynamics across two growing seasons (2023 and 2024). Six key insect variables—namely, the number of plants infested with larvae, number of damaged plants, total number of larvae, percentage infestation, percentage damage intensity, and percentage of damaged plants at four maize planting dates at May 15^th, May 29^th, June 12^nd, and June 26^th at field conditions. The results showed that the six variables tested on S. frugiperda recorded three activity peaks at each of the different maize planting dates in the season, starting to appear 15 days after planting. We conducted this study using correlation analysis and a heat map of Euclidean distance measures to illustrate within-season relationships among pest indicators and to identify between-season differences in pest patterns between the different sowing dates. For the two seasons, correlation analysis revealed consistently strong positive inter-correlations among all insect variables for all four planting dates, where the presence of infestation is directly and proportionally linked to observable plant damage. Euclidean distance analysis, applied across both seasons, consistently demonstrated that the first planting date in both 2023 and 2024 exhibited a uniquely low pest pressure profile. This indicates the existence of a significant low-pest window associated with the earliest planting. A clear trend of increasing pest pressure was observed across subsequent planting dates (second, third, and fourth) within both seasons. It is possible to draw the conclusion that the Euclidean distance heatmap shows a distinct pattern of variation in insect parameters between the 2023 and 2024 sowing dates; in terms of infestation and damage, the first date differs greatly from all other sowing dates. Early planting on May 15^th often helps to reduce autumn armyworm population dynamics, larval density, and consequent damage throughout the two seasons. Conversely, late planting on June 26^th causes more damage to maize and higher rates of FAW infestation. This data facilitates the development of date-specific pest control plans by helping to understand the dynamics of pests.