This study investigates how outdoor environmental factors and wind direction influence the performance of air-source heat pumps in cooling mode. Air-source heat pumps are a critical clean-energy technology promoted by countries to address rising energy demand and reduce carbon emissions. Using the 21st model of moderated mediation analysis in SPSS Process Macro, the research found that external temperature, wind direction, and relative humidity impact the condenser’s condensation temperature by 23.78%, 7.38%, and 4.20% (It has been obtained through value as an effect, rather than through an increase or decrease), respectively. The analysis also revealed negative indirect effects, with wind speed reducing the evaporator’s evaporation temperature by 2.55% and outdoor temperature lowering it by 20.76%. Furthermore, wind direction decreased the evaporator temperature by 0.13%. The weather is clear, with no clouds and no precipitation. The mathematical model developed for the cooling mode provides a tool for forecasting future evaporator temperatures. This approach offers valuable insights for air-source heat pump manufacturers and for designers of condensers and evaporators, and it contributes to carbon emission reduction strategies. Although the results were derived for Istanbul, Turkey, the effect coefficients estimated from the data can be applied to other significant locations.