The study aimed to elucidate previously observed associations between morningness-eveningness and seasonality by analysing their distinct aspects separately: morning affect (MA) and time-of-day preference, different seasonal types and patterns (winter, summer, etc.), the degree of seasonality and perceived negative impact of seasonality. Students from Warsaw (N=522) completed the Seasonal Pattern Assessment Questionnaire and the Composite Scale of Morningness. Winter seasonality was related to lower MA, but unrelated to time-of-day preference. Global seasonality score was negatively associated with MA in winter seasonality, but not in other seasonality patterns, and unrelated to time-of-day preference. These associations remained significant after controlling for sex, age and season of assessment. It is concluded that winter seasonality is related to low MA, but not to time-of-day preference. The above results indicate that MA can be considered as an all year round indicator of proneness to winter seasonality and eventually to seasonal affective disorder. The results also suggest that MA and time-of-day preference should be analysed separately in future research on morningness-eveningness.