Many marine species, including anemones, snails, jellyfish, coral and fish, are venomous to humans, causing serious injuries or even death. Most of these animals live in warm, shallow waters, which increases the chances of an encounter with them. The majority of these interactions with humans are accidental; however, it is not well known under which circumstances (if any) these encounters are more likely to happen. A smart-city initiative was launched for A Lanzada beach (NW Spain) in the summer of 2014. As part of this initiative, lifeguards collated data on all incidents occurring on the beach, including weever fish stings. Additionally, a number of environmental parameters were monitored. Using this unique information, statistical models were developed to evaluate under which environmental conditions beach users would be more likely to be stung by lesser weevers. The optimal model showed that stings were more likely at the southern end of this 2.7 km long beach, pointing to differences in sediment composition along the beach as a key factor. Moreover, warmer sea water and higher air temperature increased the chances of being stung. Furthermore, stings increased at low tide and decreased under strong meridional wind conditions. Finally, the number of stings increased with beach occupation up to a levelling-off point. All this suggests that a combination of fish behaviour and favourable climate conditions for beachgoers increases the chances of suffering an accidental encounter with lesser weever fish. Our results, based on basic environmental information, constitute a simple tool that could be used to provide precautionary advice to beach users in order to avoid accidental encounters with lesser weever fish.