Rithucharya specifies the activities required to be done during the different rithus or seasons. The Seasons taken into account in Rithucharya are:

Hemantha - Winter
Sisira- Cold/Dewy Season
Grishma- Summer
Varsha- Rainy Season
Sarath- Autumn

These have a bearing influence on Dinacharya. For example, in summer daytime rest is recommended whereas in winter it is considered unhealthy.