päiväaikainen

Päiväaikainen is a Finnish adjective meaning "occurring during the daytime" or "daytime". Etymologically it combines päivä (day) and aikainen (timely, early), and is used to describe phenomena, activities or conditions that take place in daylight hours as opposed to at night.

In ecology and biology the term is used similarly to "diurnal" to classify animals and plants that are active or open during the day. In everyday language it describes schedules and services, for example päiväaikainen työ (daytime work), päiväaikainen koulutus (daytime education) or päiväaikainen palvelu (daytime service). In medicine and health contexts the adjective can distinguish symptoms, measurements or treatments that occur or are applied in daytime, such as päiväaikainen verenpaine (daytime blood pressure).

Päiväaikainen contrasts with yöaikainen (nocturnal, nighttime). It is widely used in formal and informal registers and appears in compound expressions and administrative terminology (e.g., päiväaikainen valvonta, daytime supervision). As an adjective it conforms to Finnish inflection patterns and is often combined with nouns to specify temporal characteristics of activities, phenomena or services.