What the sources say happens in your month

Chosen when: Which month: January

Blacklegged ticks, the Lyme disease ticks, are active whenever outdoor temperatures are above 40 F, so a mild January day counts (MDHHS). Wildlife control by a DNR permittee may happen at any time of year in places closed to hunting or that bar firearm discharge, and at any time inside the house, buildings and yard of the person who complained.

Try first: Check the current MDHHS pages and your local health department for this year's numbers.

· Mosquito and tick season in Michigan: what the state has counted

Chosen when: Which month: February

Blacklegged ticks are active whenever outdoor temperatures are above 40 F (MDHHS). A permittee may act at any time of year within a complainant's house, buildings and yard, and in places closed to hunting or that bar firearm discharge (DNR). We found no sourced date for when mice move in, so the calendar does not give one.

Try first: Check the current MDHHS pages and your local health department for this year's numbers.

· Mosquito and tick season in Michigan: what the state has counted

Chosen when: Which month: March

Blacklegged ticks are active on any day above 40 F (MDHHS). DNR permittees outside closed areas must wait until April 1, though a complainant's own yard and closed-to-hunting places are open all year. Michigan termite swarm dates are not sourced, so none is shown.

Try first: Check the current MDHHS pages and your local health department for this year's numbers.

· Mosquito and tick season in Michigan: what the state has counted

Chosen when: Which month: April

April 1 opens the DNR window for nuisance animal control outside closed areas, and it runs to September 30. Brown marmorated stink bug adults emerge late April to early May (Michigan Invasive Species Program). Blacklegged ticks are active above 40 F.

Try first: Check the current MDHHS pages and your local health department for this year's numbers.

· Mosquito and tick season in Michigan: what the state has counted

Chosen when: Which month: May

American dog ticks become active early May and stay active to November (MDHHS). Stink bug adults emerge in early May and eggs are laid May through August. The bat maternity season begins in roughly mid-May, and DNR's two documents differ slightly on the dates, so exclusion is delayed unless human health requires it.

Try first: Check the current MDHHS pages and your local health department for this year's numbers.

· Mosquito and tick season in Michigan: what the state has counted

Chosen when: Which month: June

The bat maternity season is under way: DNR's public page says typically May to mid-August and its circular says to avoid June 1 through August 15. American dog ticks and blacklegged ticks are active. Stink bug eggs are being laid.

Try first: Check the current MDHHS pages and your local health department for this year's numbers.

· Mosquito and tick season in Michigan: what the state has counted

Chosen when: Which month: July

West Nile risk begins to rise: Oakland County says it is highest from late July through September, and MDHHS says outbreaks have occurred every summer since 2002. Bats are still within DNR's maternity window. American dog ticks are active.

Try first: Check the current MDHHS pages and your local health department for this year's numbers.

· Mosquito and tick season in Michigan: what the state has counted

Chosen when: Which month: August

West Nile risk is within its late July to September peak (Oakland County). Bats remain in their maternity window until about mid-August, after which exclusion can begin. Purdue says cluster flies start seeking winter sites from late August, a Midwest source that is not Michigan State University.

Try first: Check the current MDHHS pages and your local health department for this year's numbers.

· Mosquito and tick season in Michigan: what the state has counted

Chosen when: Which month: September

West Nile risk runs through September (Oakland County). Stink bugs look for overwintering sites, including inside buildings, from September (Michigan Invasive Species Program), and cluster flies and boxelder bugs do the same according to out-of-state extension services. DNR's April to September window outside closed areas ends on September 30. Bat exclusion can proceed once the young can fly.

Try first: Check the current MDHHS pages and your local health department for this year's numbers.

· Mosquito and tick season in Michigan: what the state has counted

Chosen when: Which month: October

American dog ticks are active until November and blacklegged ticks whenever it is above 40 F (MDHHS). Fall invaders such as boxelder bugs congregate on south-facing walls (University of Wisconsin) and the stink bug season continues. MDHHS's latest 2026 arbovirus summary is dated October 16 and is provisional. Mouse move-in dates are not sourced and are left out.

Try first: Check the current MDHHS pages and your local health department for this year's numbers.

· Mosquito and tick season in Michigan: what the state has counted

Chosen when: Which month: November

American dog ticks stay active into November (MDHHS), and blacklegged ticks are active on any day above 40 F. DNR's April to September window outside closed areas has ended, though closed-to-hunting places and a complainant's own yard remain open to permittees.

Try first: Check the current MDHHS pages and your local health department for this year's numbers.

· Mosquito and tick season in Michigan: what the state has counted

Chosen when: Which month: December

Blacklegged ticks are active whenever outdoor temperatures are above 40 F (MDHHS), even in December. Wildlife control in closed-to-hunting places and within a complainant's house, buildings and yard may happen at any time (DNR). The sources we cite say nothing more about winter pest activity.

Try first: Check the current MDHHS pages and your local health department for this year's numbers.

· Mosquito and tick season in Michigan: what the state has counted