Why ground floor changes the whole calculation
In an upper flat, a window's main danger is a fall. At ground level the same open window is simply an exit onto a pavement, a car park, or a street — and summer is when it stays open for hours, often while you are in another room or asleep. A cat who has watched birds through that glass all spring knows exactly what is on the other side, and a gap that looks head-sized to you is an invitation to her. Every fitting you choose has to answer one test: could she push through it, squeeze through it, or be trapped in it, at three in the morning, unobserved?
Choose restrictors and screens that resist a cat's full weight
Fit window restrictors that lock the opening to a narrow gap her head cannot pass, and choose rigid framed mesh screens, firmly fixed into the frame, over loose netting pressed into place. A determined cat leans, climbs, and launches at screens after insects, so press every fitted screen hard from inside with both hands before you trust it; any flex, rattle, or lifting corner means refitting, not hoping. On rented flats, ask the landlord before drilling, and keep the fittings — restrictor cables and framed screens usually satisfy landlords because they also improve security at ground level.
Handle tilt-and-turn windows as a trapping hazard
Tilt-and-turn windows opened on the tilt setting leave a V-shaped gap along the sides that has seriously injured cats who tried to climb through and slid down into the narrowing wedge. In a cat's ground-floor flat, either block those side gaps with purpose-made guards, keep the window fully closed, or open it flat on its hinges with a restrictor and screen fitted. Never leave a tilted window as the room's only ventilation while you are out. The same caution applies to any window left open a crack on a latch — a crack that admits a paw admits leverage.
Build summer habits around the safe windows
Decide which windows are the summer windows — screened, restricted, and checked — and keep the rest closed however warm the flat gets, using fans to move air from the safe openings. Do a weekly summer check of every screen and restrictor, because heat, use, and one determined shoulder can loosen fixings gradually. If the cat spends hours on a sill, give her a perch just inside the screen so the window remains a viewing spot rather than a project, and keep bird feeders outside positioned so she watches from indoors instead of launching at the glass. At night, when open windows are hardest to supervise, the restricted setting is the maximum opening.
If she gets out through a window anyway
Ground-floor escapes usually end nearby: cats leaving a flat this way tend to hide in the nearest cover — under cars, in bin stores, behind planters — especially in daylight. Search those spots quietly first, then knock on the flats around yours, whose gardens and sheds she can reach in seconds. Go out again at dusk with a torch, when eyes reflect and streets quieten. The Lost Pet Alert System on KinsLe comes with every profile at no charge, and a person who finds her can send you a message through the alert instead of guessing who she belongs to.