Tick season begins record early this year with sightings as far north as Oulu

The first ticks of the season have been spotted exceptionally early this year, with observations reported as far north as the Oulu region in mid-March, according to a report by Finnish public broadcaster Yle. Nearly 100 sightings have been logged nationwide in the past month via the Punkkilive tracking platform, maintained by the University of Turku and pharmaceutical company Pfizer.

Marko Mutanen, professor of molecular systematics and bioinformatics at the University of Oulu, describes the early start to the tick season as unusual. “While ticks are early risers in spring, it’s not typical for the season to begin in mid-March,” he said.

Four tick sightings have been reported in the Oulu area through the Punkkilive mapping app, where anyone can submit observations. The early emergence is attributed to snow-free ground and warm weather. Ticks overwinter in leaf litter and become active once temperatures rise above freezing and snow cover melts.

“With temperatures around 5–6°C and little snow in forests, conditions are met. It’s not surprising, but it’s unusual for this to happen in mid-March,” Mutanen noted.

The Siberian tick, the dominant species in the Oulu region, is adapted to continental climates and survives harsh winters. Its population has not collapsed despite the low-snow, cold winter. Meanwhile, ticks have spread inland from coastal areas in recent years, appearing in places like Kiiminki, where they were previously absent.

“Ticks travel to new areas via dogs or humans. If conditions allow, they establish themselves inland, which isn’t surprising at these latitudes,” Mutanen explained.

In Lapland and northeastern Finland, ticks have not formed permanent populations, likely due to short summers and unsuitable habitats. “Many assume winter is the deciding factor, but for invertebrates, summer conditions are more critical. They must complete life stages, and a short summer can be fatal,” Mutanen said.

He advises starting tick checks now in snow-free areas. “We’re already at the point where tick inspections should be done,” he reminded. In May 2025, a family in Oulu collected nearly 20 ticks in just 30 minutes using a blanket drag in their yard.