The subtropics are a climatic region of the world. They lie between the tropics and temperate zones. The temperate zones are more towards the geographical poles, the tropics are more towards the equator. Very often, subtropics are defined through the climate: In general, the mean temperature year round is above 20 °C (68 °F), the coldest month of the year has a temperature below this mark. Unlike in a tropical climate, snow and frost do occur in subtropical areas. Humid subtropical climates have hot summers and cool to warm winters with abundant rainfall in every season. Mediterranean climates with their warm to hot dry summers and cool to mild wet winters are often considered subtropical. Subtropical deserts have very hot summers and cool to warm winters, with little rain. Different subtropical areas have different types of plants. Humid subtropical areas have evergreen and deciduous trees, Mediterranean areas have scrub, and deserts have cacti.