Number of "mosquito days" is trending downward in San Antonio
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The number of "mosquito days" — that is, those with the hot and humid weather the vampiric insects crave — has trended downward in San Antonio 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 average relative humidity of 42% or higher, plus daily temperatures of 50°–95°.
Why it matters: Mosquitoes are more than just a nuisance — they're a public health threat, carrying diseases such as malaria, West Nile and Zika.
- On Friday, Metro Health confirmed a mosquito pool tested positive for the West Nile virus. The infected pool was on the Southwest Side.
By the numbers: San Antonio had 137 mosquito days in 2022, compared with 222 in 1979 — a decrease of 85 days.
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.
The intrigue: San Antonio temperatures might be too hot for mosquitoes, the analysis notes.
- They don't thrive in temperatures above 95°.
- The Texas heat wave has heat indices reaching upward of 120° across parts of the Lone Star State, Axios' Andrew Freedman reports.
Of note: Other factors, such as rainfall and drought, can also influence mosquito activity since they breed in standing water.