This prepositional phrase specifies a search query related to air travel. It targets departures originating from a single, unspecified airport during the month of January. An example would be searching for airfare departing from London Heathrow during January.
Focusing a search on a specific month and departure point allows for more refined results, potentially revealing lower fares and more convenient schedules. Historically, January is often considered a less busy travel month after the holiday season, which can lead to airlines offering competitive pricing to attract passengers. This targeted approach is beneficial for travelers seeking the best possible value and avoiding the complexities of broader searches.