Mosquito surveillance data reports the abundance of various
species of mosquitoes in San Mateo County.
Different mosquito species have different seasonal life cycles,
bite different hosts at different times of day, and transmit
different diseases. It’s important for District staff to know
what mosquito species are present in order to minimize annoyance
and, more importantly, disease risk to humans and domestic
These graphs track the number of mosquitoes of each species
(vertical axis) by month (horizontal axis). These are frequently
compared to a five-year average of each mosquito species by
month, allowing staff to determine whether we have more, less, or
about the same mosquito populations as most years.