The short answer
Cockroach and rodent risk is a year-round baseline for any restaurant — food, water, heat and a shared back-alley ecosystem are present all year, and that risk doesn't switch off between seasons. On top of that baseline, a few seasonal pressure points stand out: February to April is Hong Kong's humid spring, when storage areas see more booklice and silverfish activity; April to July is termite swarming season, when winged termites drawn to light can signal a mature colony nearby; mosquitoes are active roughly March to November, busiest May to September, with outdoor seating and back alleys most exposed; and August to October sees more wasp activity around outdoor areas. These windows are compiled from operational experience, not a scientific paper — check FEHD's own published data if you need to verify the mosquito figures.
Why does pest prevention for restaurants follow a calendar?
A restaurant's pest risk is different from a home's — food, water, heat, constant deliveries and a shared back-alley ecosystem are all present at once, so cockroach and rodent risk is essentially a year-round baseline that doesn't disappear once a particular month passes. On top of that baseline, different pests become more likely to show up in different seasons, and it's worth stepping up checks accordingly. What follows is practical, operational guidance, not a scientific paper — check FEHD's own published data if you want to verify any specific figure.
February to April: humid spring is hardest on storage areas
Hong Kong's humid spring weather (回南天) is when damp-loving pests like booklice and silverfish are most active, and dry-goods storage rooms and floor-level stock are most exposed. What a restaurant can do: run dehumidifiers harder in storage areas, keep dry goods off the floor and away from walls, and check regularly for mould or damp cardboard.
April to July: termite swarming season — watch front-of-house lighting
This window is termite swarming season, and winged termites are drawn to light — dinner-service lighting at the front of house can easily attract them. Seeing swarmers doesn't automatically mean the premises already has termites, but it does suggest a mature colony nearby, worth having checked out. For source-treatment detail, see termites.
March to November (peak May–September): outdoor seating and back-alley standing water
FEHD's own data shows mosquitoes are active in Hong Kong roughly from March to November, generally busiest from May to September. Restaurants with outdoor seating or back-alley exposure face higher risk — pot-plant trays, air-conditioner drip pans, and standing water in back alleys are all breeding grounds, and the risk spikes further after heavy rain or a typhoon. What a restaurant can do: check and tip out these standing-water spots on a regular schedule, rather than waiting for a customer complaint.
August to October: watch for wasps around outdoor dining areas
This window sees more wasp and hornet activity, and premises with outdoor dining, awnings, or air-conditioning units should watch for nests forming. Don't attempt to remove a nest yourself — it needs professional assessment and handling. For who's responsible for removal, see our wasp nest removal guide.
A year at a glance
| Season | Pest pressure | What to check |
|---|---|---|
| Feb–Apr (humid spring) | Booklice and silverfish active in damp storage areas | Dehumidify storage, keep dry goods off floor and wall, check for mould |
| Apr–Jul (termite swarming) | Swarmers drawn to light may signal a mature colony nearby | Watch front-of-house lighting at night for swarmers, check timber fittings |
| Mar–Nov, peak May–Sep | Mosquito pressure around outdoor seating and back alleys | Tip out pot trays, AC drip pans, and back-alley standing water regularly |
| Aug–Oct | More wasp activity around outdoor dining areas | Check awnings, AC units and back-alley eaves — don't remove a nest yourself |