The 2025–2026 winter was mild, so more ticks survived. Then the spring came early and there was more rainfall than usual, which gave ticks a head start.
There is no easy way to say this: emergency department visits for tick bites were up more than 50% in April compared to the previous year. Nymphal ticks, the ones most likely to transmit Lyme disease, emerged earlier and in higher numbers than usual. If you’re worried about ticks this year, that’s reasonable.
The winter of 2025–2026 was mild across much of New England. Cold winters are one of the few natural checks on tick populations. Extended freezing temperatures make it hard for ticks to overwinter for survival, particularly for the smaller nymphs that shelter in leaf litter. The mild winter didn’t function as a check on the tick population this year, and this was only made worse by the unseasonably warm temperatures seen in March and April.
Spring was also wet this year, which ticks need. Humidity helps them survive for long enough to quest, which means waiting on tips of grass or low vegetation with their legs outstretched for a host to pass by. In a dry spring, ticks cannot do this as easily because they risk desiccation. This year, conditions stayed wet enough to where that also failed to check the population size.
Nymphal blacklegged ticks are roughly the size of a poppy seed. They’re so small that they’re hard to spot and are therefore responsible for the majority of Lyme disease transmissions. This year, there were more nymphs due to the factors explained a bit earlier.
While ticks are especially bad in 2026, this is part of a long-term trend that’s not going anywhere. Tick populations have been trending upward for decades. And the conditions that drove this year’s early surge are consistent with the broader pattern of milder winters and longer active seasons.
If you're concerned about tick exposure on your Chelmsford or Cambridge property this season, Mosquito Squad of Chelmsford & Cambridge can help. Mosquito Squad targets the places where ticks wait for hosts, reducing populations by up to 90% with treatments every 21 days.
