Quinoa (Chenopodium quinoa), a traditional Andean crop, has emerged as a climate-resilient and nutrient-dense crop, with significant potential for cultivation in resource-constrained environments. The present study evaluated the agro-climatic adaptability and phenotypic performance of eleven quinoa accessions across two cropping seasons, namely kharif (2023) and rabi (2023-24) under subtropical Indian conditions. Climatic suitability was assessed using temperature, precipitation and relative humidity layers modelled in Google Earth Engine based on global climate datasets. Suitability mapping indicated that extensive regions across Asia and Africa, including arid and semi-arid areas, are suitable for quinoa cultivation under supplemented irrigation conditions, despite low rainfall. Field evaluation under a randomized complete block design revealed strong seasonal effects on flowering, plant height, thousand grain weight and single-plant yield, with rabi significantly outperforming kharif for all major traits. Kharif grown quinoa crop showed a reduction of 7.47 % in DTF, 38.10 % in PHT, 85.76 % in TGW and 85.83 % in SPY in comparison to rabi grown crop. The results of ANOVA and PCA indicate that quinoa cultivation in subtropical India is substantially more suitable during the rabi season and that Co-407, D-12047 and BO-51 are promising candidates for cultivation and further breeding aimed at productivity and seasonal adaptation in non-traditional agro-ecologies.