Some quick facts about lightning bugs, also known as fireflies

Don’t miss the full story from our staff writer Matt Delaney, whose reporting is the basis of this AI-assisted article.

The Washington region is experiencing what some experts describe as an exceptional firefly season in 2025, with lightning bugs appearing in abundant numbers from Rock Creek Park to the Maryland and Virginia suburbs. Here are some quick facts about lightning bugs, also known as fireflies:

• Seasonal timing and habitat preferences: Peak firefly season in the mid-Atlantic runs from late May until mid-July, with the insects preferring rural areas with unmanicured meadows over urban environments due to light pollution and cramped habitats in cities.

• Weather dependency for population success: A forgiving winter with adequate moisture followed by consistent spring rainfall creates ideal conditions for firefly larvae, as wet soil supports the snails, slugs, and earthworms that serve as their primary food source.

• Urban challenges and adaptability: While pesticides, insecticides and light pollution in cities harm firefly populations by affecting their food supply and mating behavior, the big dipper firefly species proves most adaptable to urban green spaces.

• Population fluctuation patterns: Firefly populations naturally bounce up and down in short periods due to their brief lifespans, making year-to-year variations normal rather than indicative of long-term population trends.

• Mating behavior requirements: Lightning bugs need darkness to attract mates through their bioluminescent displays, making light pollution a significant threat to their reproductive success in urban areas.

READ MORE: Fireflies light up D.C., thanks to good weather earlier in year