Русско-англо-русский юридический словарь

Seasonal demand: Some services do not have an all year round demand, they might be required only at a certain period of time. Seasons all over the world are very diverse. Seasonal demands create many problems to service organizations, such as: idling the capacity, fixed cost and excess expenditure on marketing and promotions. (Wikipedia)

On top of that, although the increased security on the border is serving as a deterrent, we found that it has also resulted in trapping people inside the US who in the past might have come over for seasonal work and returned back to their home country to re-join their families. (Huffington Post)

Eleven percent of job vacancies were for temporary or seasonal work. (Hutchinson Leader)

A leap year (also known as an intercalary year or bissextile year) is a calendar year containing one additional day (or, in the case of lunisolar calendars, a month) added to keep the calendar year synchronized with the astronomical or seasonal year. [...] For example, in the Gregorian calendar, each leap year has 366 days instead of the usual 365, by extending February to 29 days rather than the common 28. (Wikipedia)