Why this walk needs a different plan in summer
The Comber Greenway is one of the most-used dog walks between East Belfast and Comber, and for most of the year that's exactly why it works — flat, well-surfaced, easy to follow, no stiles or awkward gates. But it's an old railway line, and old railway lines were built dead straight through open ground, which means long stretches with nothing overhead. In February that's fine; the problem is invisible. In July it's the whole ball game.
The thing that catches people out isn't the air temperature, it's the surface. A tarmac path in direct sun on a 22-degree Belfast day can sit noticeably hotter than the air above it, and it stays that way for hours after the sun has moved round. If you're used to judging 'is it too hot for a walk' by checking your phone's weather app, this route will occasionally prove you wrong.
How to actually test the ground before you set off
Forget guessing. Press the back of your hand — not your palm, your hand is more sensitive on the back — flat against the tarmac and hold it there. If you can't keep it down comfortably for around seven seconds, it's too hot for paw pads, full stop. Dogs have tougher pads than we imagine, but they're not immune, and the greenway's tarmac is the same material as a car park, which is exactly the surface vets warn about.
Do this test in a few spots, not just at the start. The section near the Billy Neill playing fields on the Dundonald side can feel completely different underfoot to the open stretch heading towards Comber, simply because one has partial tree cover and the other doesn't. If in doubt, walk the grass verge where it exists rather than the path itself — it's rougher going but considerably cooler.
When to go: the honest timing advice
In summer, the greenway is genuinely a different walk depending on the hour. Early morning — before the school run traffic builds and before about nine — is the best window: the tarmac hasn't had time to soak up heat, the air is still cool off the fields, and you'll share the path mostly with other dog walkers and the odd early cyclist rather than the lunchtime rush of commuters cutting through on bikes.
Midday and early afternoon in a heatwave are the times to actively avoid, not just discourage. There's very little relief along most of the route and no natural water for dogs to cool off in beyond the odd roadside ditch, which isn't something you want them drinking from anyway. Evening, from about seven onwards, is the other good window — the path has usually started to release its heat by then, though on a still, warm evening near the hedgerows you'll meet midges, so it's a trade-off worth knowing about rather than being caught out by.
Where the shade actually is (and where there isn't any)
This is the detail most guides skip. The Dundonald end, particularly around the old cutting sections and where the path dips below the level of the surrounding land, has proper tree cover in places — mature growth either side that throws real shade for a decent stretch mid-morning and mid-afternoon. That's your best bet for a summer walk with a dog who overheats easily.
As the greenway pushes on towards Comber, the landscape opens out into farmland either side and the tree cover largely disappears. It's a lovely walk for the views across to the Comber hills and it's genuinely quieter underfoot than the East Belfast end, but on a bright day it's exposed the whole way, and there's nowhere to duck into if a dog starts flagging. If you've got a flat-faced breed, an older dog, or anything with a heavy or dark coat, treat the Comber-end stretch as a cooler-months route and save it for spring or autumn.
Where to start and which entrance is quieter
There are several access points along the greenway feeding in from the surrounding East Belfast estates, Dundonald and towards Comber itself, and most have some form of parking nearby, though it's worth checking current signage rather than assuming — spaces can be tight near the more popular entrances, especially at weekends. The Dundonald end tends to be the busier access point, partly because of the playing fields and leisure centre nearby drawing families and dog walkers at the same time.
If you want a quieter start, the stretches further out towards Comber generally see fewer people, particularly on a weekday morning. It is a shared path used heavily by cyclists commuting in and out of Belfast, so regardless of which end you choose, keep dogs close on the approach to blind bends and be ready to call them in — bikes come through at a fair lick and don't always ring a bell first.
Water, breaks and reading a dog that's struggling
Carry water for the dog as a matter of course in summer — don't rely on finding a tap or fountain along the route, and don't let a dog drink from field ditches or stagnant puddles beside the path, both of which appear in dry spells and can carry more than they look like they would. A collapsible bowl in a pocket is worth the minor faff.
Watch for the usual signs rather than pushing on because you're only halfway: heavy panting that doesn't ease when you stop, reluctance to keep moving, wobbliness, or gums that look brighter red than normal. If you see any of that, get into whatever shade you can find, offer water in small amounts, and head back the shortest way rather than completing the loop. It's rarely dramatic if you catch it early, but it escalates fast if you don't.
When the walk just isn't sensible that day
Some days in Belfast — not many, but some — the sensible call is to skip the greenway altogether and do something shorter and shaded, or nothing outdoor at all until evening. That's a harder decision to make with a dog who's used to their walk and lets you know about it, but it's the right one on the days the tarmac won't cool down.
It's also the sort of day that makes people think about day care rather than fitting a walk around work. If you're local to Carryduff, Newtownbreda or the wider south Belfast and Down area and you'd rather your dog spent a scorching afternoon somewhere cool and supervised than pacing a hot garden, that's exactly the kind of thing doggy day care near Belfast is for — we see a noticeable uptick in enquiries at Johnny's Doggy Hotel on the hottest days of the year, for that reason.