Every summer there is a time when thousands of giant flying ants leave their nests all at the same time - a spectacle nicknamed Flying Ant Day.
The phenomenon, which usually happens sometime between late June and August, will see giant black swarming clouds of the winged insects descend on streets and gardens across the UK.
July is often their most favoured month - and while the event is dubbed 'flying ant day' their release often builds over several days before they are seen in their biggest numbers.
Different weather patterns across the UK can also mean that exact date may differ by a day or two depending on where you live and how the different colonies react to more localised changes.
But swarms of the insects are common around this time of year as they take to the skies as part of their 'nuptial flight' phase of reproduction so when could the masses arrive and should you try and keep them out of your home?
What happened last year?
Last year Flying Ant Day took place in most parts of the country between early to mid July when the creatures appeared in their biggest numbers.
Often encouraged by a spell of hotter and drier weather, sometimes after a period of very heavy rain, one particular swarm was picked up on Met Office radars after some particularly humid weather in the south east.
During their flight the young queen ants will mate with the strongest males before landing and starting their own colony in a new location.
The Natural History Museum explains that it could be more correct to call the event 'flying ant season' as there is often more than one occasion when the critters are going to be seen over the summer months moving in their thousands.
It explains: "This annual swarming event usually occurs in July or August and coincides with a period of hot and humid weather. Winged ants appear at different times around the country and local weather conditions are critical for the coordination of swarming activity."
And although most of us may not relish the thought of thousands of the winged critters buzzing above our heads, it can be quite a sight.
You can see them from space
Last year's sighting by the Met Office, in which a large swarm was picked up on weather radars over London as forecasters kept an eye on the skies ahead of the Wimbledon finals, is not the only time the flying pests have been detected on high-tech cameras.
The Met Office's radar picked up something spreading over Kent, East and West Sussex, Hampshire and Dorset - and initially thought it could be a band of rain. But a closer look revealed it was indeed thousands of flying ants.
For people living around the coast, flying ants can present an altogether different challenge because the creatures produce formic acid, which can prove irresistible to seagulls. Birds love to gorge on the ants and the acid's effect can make them seem almost drunk and sightings of them stumbling along the seafront are not uncommon.
Should you get rid of them?
Flying ants will swam in the summer months - because the heat, wind patterns and humidity is felt to be just right for them and gathering in greater numbers when they leave the safety of their nests helps to protect them from predators.
Other than being annoying, the flying ants should do very little harm. And while their arrival and breeding behaviour spells the start of new colonies they can prove extremely beneficial to outdoor spaces.
During June and July you are likely to spot hundreds of them crawling across the ground as they get ready to move and they can help to aerate the soil while also controlling other pests not to mention providing a potential and plentiful food source for many birds.
Pest controllers Rentokil advise keeping doors and windows closed if the ants are circulating in particularly high numbers, or using fly screens and curtains to keep them out if the weather is really too warm to keep the house shut up.
And their arrival is short lived, so after a few days you should notice that any significant populations you have seen in your local area will begin disappearing.
But if you do find some very near your home you may wish to discourage the potential for new visitors.
Experts say a few weeks before the ants rise large unexplained piles of soil can start appearing on the grass above nests and this can sometimes be the first sign that new creatures are about to emerge. Disrupting any nests or ant mounds you find in your garden can be the best place to start in reducing the risk of them coming indoors in large swarms.