Soil temperature is an important factor influencing crop growth. Within limits, a higher soil temperature will promote crop growth, particularly in cool climates. The application of compost increases the soil temperature, probably by drying the soil surface, but the relationship between soil temperature and soil water remains unclear. We conducted pot and field experiments on a bare Andosol in a cool climate region. The pot experiment examined the effects of compost application on soil temperature and evaporation, and the field experiment examined the effects of the properties and amount of compost on soil temperature. Pots with compost had a higher soil temperature and less evaporation than pots without compost. The decrease in evaporation and the increase in soil temperature by compost application were significantly correlated. The field experiment included 15 treatments: 12 compost treatments (four types of compost × three levels) and three chemical fertilizer treatments (one type of fertilizer × three levels). There was a significant correlation between soil temperature and the dry weight of the applied compost. We conclude that compost application increases soil temperature by decreasing evaporation from the soil surface. In addition, soil temperature increases with increasing dry weight of the compost applied, regardless of the chemical properties.