In this paper, a hygrothermal model with capability of including hysteresis effect was developed in Python. Wind-driven rain (WDR) and solar radiation were incorporated to create dynamic climate conditions to mimic the climate loads in real situation. A hysteresis model from literature was integrated into the hygrothermal model. The model was validated against experimental data of a date palm concrete wall found in the literature. Incorporating hysteresis improved modeling accuracy of relative humidity (RH) values at three monitored depths, reducing the maximum error between simulation and measurement by 2.47% and lowering the mean absolute error (MAE) by 1.3%. Following validation, the hygrothermal performance of an eastward-oriented hempcrete wall was analyzed under Vancouver's future climate conditions. The results indicated that hysteresis has a minimal impact on the simulation outcomes of the hempcrete layer when rain penetration was excluded from the simulation. RH and moisture content (MC) showed the MAEs of less than 1% when comparing simulations with and without hysteresis. However, when rain penetration was included as a moisture source on the exterior surface of the hempcrete, MC discrepancies were increased between the models with and without hysteresis. The MAE for MC was 5.04%, with a maximum difference of 7.17%.