Raleigh is growing more hospitable to mosquitoes
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The number of "mosquito days" — that is, those with the hot and humid weather the flying insects crave — has risen in Raleigh over the past several decades.
- A report from nonprofit climate science research organization Climate Central, defines a "mosquito day" as one with average relative humidity of 42% or higher, plus daily temperatures of 50°–95° F.
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.
- 12 human cases of West Nile disease were reported in North Carolina last year, according to the Centers for Disease Control and Prevention. None have been reported so far this year.
By the numbers: Raleigh was among the 71% of locations Climate Central analyzed in its report that saw an increase in mosquito days between 1979 and 2022.
- The area saw 191 mosquito days in 2022, compared to 172 in 1979 — an increase of 19.
- That's higher than the national average increase of 16 days.
The big picture: Between 1979 and 2022, the Southeast had the highest average annual mosquito days of any other region, with 218 (60% of the year).
Threat level: Five locally-acquired cases were identified in Florida and Texas, the CDC reported just last month, the first time since 2003 that the disease has been acquired in the United States.
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.
- That's not great news for the Triangle, which has seen 4.45" of rain in the last 30 days, according to WRAL — or .29" more than normal.
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 locals and skeptics who view them as tampering with the natural ecosystem.
The bottom line: Mosquitoes — and the diseases they sometimes carry — are shaping up as one more climate change-induced problem for many local officials to worry about.