Soil water characteristic curve (SWCC) is a fundamental property of geomaterials to determine its unsaturated behavior. The SWCC is essentially important to design the geo-infrastructures such as earthen dams and levees, pavement subgrade, clay liners, soil covers, etc., and determine the ground response under varied environmental conditions. Although there are numerous methods to determine the SWCC in the laboratory, field measurements and evaluation of SWCC are very limited, especially in the geo-environmental application. The objective of this study was to determine and evaluate the change in the SWCC flow parameters of an earthen final cover of landfill under varied climatic conditions. To fulfill the objective, field test section (lysimeter) was instrumented with pairs of moisture content sensors and tensiometers at varied depths to capture the hydraulic response of the cover to a series of variable environmental cycles. The field SWCCs were monitored and evaluated for two years. The SWCCs determined from field investigation were also described mathematically using the van Genuchten’s equation, and two extreme conditions: maximum drying curve (MDC) and maximum wetting curve (MWC) were identified. Based on the field investigation, considerable changes in the SWCCs were observed at different depths. The upper portion of the earthen lysimeter was found to be significantly responsive under the influence of the environmental variation than the lower portion. Non-equilibrium occurrences were detected while portraying the field moisture-suction characteristics, especially in the lower region of the cover soil. Considerable discrepancies were observed in the van Genuchten’s curve fitting parameters in the MDC and MWC.