Background: Vitamin D deficiency, which classically manifests as bone disease is characterized by impaired bone mineralization. Because of seasonal variations in sunlight exposure, variations in vitamin D levels have been proposed to occur. Hence; the present study was conducted for evaluating the vit D levels in seasonal variations among known population in Rohilkhand Region. Materials & Methods: A total of 50 patients were enrolled in the present study. All the patients belonged to the age group of 25 to 50 years. Patient demographic data, including age, gender, and body mass index (BMI), were collected. Blood samples were taken, and biochemical values of vitamin D was recorded using FINECARE via fluorescent immunoassay (FIA) method. The entire study period of 2022 was divided into four time periods as follows: January-March, April-June, July-September and October-December. Vitamin D status in patients based on the Endocrine Society clinical practice guidelines. According to the guidelines, a vitamin D level <50 nmol/L is considered deficient, 50–74 nmol/L is considered insufficient, and ≥75 nmol/L is considered optimal. Results: Majority of the Vitamin D deficient patients were seen in January-March time period (28 percent of patients) and October-December time period (30 percent of patients). There were significantly more patients with vitamin D deficiency during the cold season than during warm/hot season. Conclusion: Due to inadequate sunlight in winters, there is comparatively higher deficiency of vitamin D.