Investigation on the climatic effects of irrigation is of great significance to fully understand the impact of water management on the Earth's environment and hydrological cycle. To comprehensively explore the effects of irrigation across different climatic regions over China, we propose a novel combined irrigation scheme (including dynamic and fixed irrigation schemes) into the Weather Research and Forecasting (WRF)‐Noah‐mosaic model. Two experiments (with and without irrigation) are designed to simulate the impacts of irrigation over China on regional climate. As irrigation increases the latent heat flux but decreases the sensible heat flux and surface temperature, and the magnitudes of corresponding change are highly dependent on the irrigation amounts and irrigation fraction, the evaporative cooling effects significantly reduce the warm bias over extensive irrigation area during crop growing seasons. Meanwhile, irrigation increases soil moisture during both irrigated and non‐irrigated seasons. Compared with the dynamic irrigation scheme, the fixed irrigation scheme results in relatively higher subsurface runoffs due to the continuous infiltration. In addition, the irrigation‐induced changes on precipitation during spring (March–May) are weaker than that during summer (June–August). The opposed effects of irrigation cooling and wetting on generating convective precipitation, and the irrigation‐induced changes in large‐scale circulation jointly give rise to the heterogeneous changes of precipitation. Besides, the subgrid‐scale irrigation scheme can capture the climatic effects of irrigation in some grids where the dominant land use types are not cropland, indicating that in mesoscale simulation, climate model coupled with subgrid‐scale irrigation scheme may improve climate variables trends attribution studies.

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