TickZone

How the tick-risk score works

Every TickZone town gets a daily 0–100 score in three colors: green (0–33, low), amber (34–66, moderate), and red (67–100, high). Here is exactly what goes into it.

The inputs

  • Local weather (Open-Meteo).Ticks quest when it's roughly above 45°F with enough humidity and recent moisture; hard freeze, drought, and extreme heat suppress them. We use today's conditions and a trailing-week moisture window, refreshed daily, and it drives the 7-day outlook.
  • Tick life-stage. Nymphal deer ticks peak in late spring and summer and cause most human Lyme cases; adults have a secondary fall peak. The score rises and falls across the year to match this calendar.
  • Local land cover (MassGIS).Ticks live in woods, edges, and brush. Each town's share of forest and open/brushy land sets how much suitable habitat exists. This is what separates a wooded town from a dense one in the same county.
  • County disease rates (MA DPH).Each county's baseline is a normalized composite of its 2025 Lyme, anaplasmosis, and babesiosis incidence rates. We use all three because Lyme reporting methods changed in 2016 and again in 2022, while anaplasmosis and babesiosis are more consistent.
  • Recent sightings (iNaturalist). Tick observations logged within about 15 miles over the last 30 days add a small, bounded nudge. It is never enough to swing the score on its own, because this data is sparse in rural areas.

How they combine

Season and weather act as a gate: a deep freeze pulls the score toward zero no matter how endemic the county. The county baseline and local habitat set how high the risk climbs when conditions allow. Recent sightings add a small bonus on top. The result is scaled to 0–100 and mapped to the three color bands.

What this is, and isn't

This is a defensible heuristic, not a validated epidemiological model. It estimates how favorable conditions are for tick activity in a place on a given day; it cannot tell you whether a specific tick carries disease. County disease rates are per-capita and annual, so they describe a county's general burden, not your individual risk. Land-cover data reflects a town's broad make-up, not your yard.

Not medical advice. If you find an attached tick or develop symptoms after a bite, contact a healthcare professional and see CDC tick-bite guidance.

Sources

Sources: Massachusetts Department of Public Health · U.S. CDC · Open-Meteo · iNaturalist · MassGIS · U.S. Census Bureau