Jul 3, 2023 - News

Houston sees fewer mosquito days

Data: Climate Central; Chart: Axios Visuals
Data: Climate Central; Chart: Axios Visuals

The number of "mosquito days" — that is, days with the hot and humid weather the flying insects crave — has trended downward in Houston over the past several decades, per a new analysis, Axios' Alex Fitzpatrick and Kavya Beheraj report.

  • The report, from nonprofit climate science research organization Climate Central, defines a "mosquito day" as one with an average relative humidity of 42% or higher, plus daily temperatures of 50° to 95°.

Why it matters: Mosquitoes are more than just a nuisance — they're a public health threat, carrying diseases such as malaria, West Nile, Zika and more.

By the numbers: Houston had 182 mosquito days in 2022, compared to 240 in 1979 — a decrease of 58 days.

The intrigue: Some locations — particularly in the South — are actually getting too hot for mosquitoes, the analysis notes.

  • Mosquitoes don't thrive in temperatures above 95° — an increasingly common reading in Southern summers.
  • The ongoing Texas heat wave has heat indices reaching upward of 120° across parts of the Lone Star State, Axios' Andrew Freedman reports.

The big picture: 71% of the 242 locations Climate Central analyzed saw an increase in mosquito days between 1979 and 2022 — of about 16 days on average.

Of note: Other factors, such as rainfall and drought, can also influence mosquito activity.

  • They breed in pools of standing water, common after major storms.

What's next: Experimental efforts to control mosquito populations by releasing genetically modified versions of the insects into the wild are underway in Florida and elsewhere.

  • Those projects, however, are controversial among some who view them as tampering with the natural ecosystem.

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