A long-standing puzzle has been why outbreaks of the flu occur seasonally rather than uniformly throughout the year.

In recent times, the trading farmers market now only occurs seasonally, replaced by weekend continental and craft markets.

The movements are generally poorly understood, but it only occurs seasonally at some localities in Argentina.

Some pools only occur seasonally while others retain enough water to be present all year.

(Some types of mold also occur seasonally and may cause similar symptoms.)

She determined that it occurred seasonally, beginning in summer and continuing until the first frost.

Fish migration between river channels and flood-plain regions occurs seasonally.

Locally and seasonally occurring at several 100 individuals m-2, they are important mediators for particulate organic matter from the sea ice to the water column.

This is why the storms occur seasonally, once summer sunshine has pushed sea temperatures beyond the threshold.

Events and exhibits in the museum occur seasonally and there are many organized playgroups for all ages.