Until last week the evening walk was ordinary. Now the clocks have gone back, the park is dark by the time you get there, and your 10 month old dog is stopping dead at shapes that were never a problem in daylight.
Nothing about your dog has changed overnight. The walk has. A bin, a bench and a hedge look like different objects in streetlight and shadow, and a dog already inclined to startle at this stage notices the difference before you do.
Why the dark makes an adolescent dog harder to walk
Your dog is working with less information: shapes rather than detail, movement at the edge of a streetlight rather than a clear view. Startling at ordinary things and reacting more than usual is already common in the second half of the first year, and low light adds a layer on top of it.
You are working with less information too. You cannot see your dog's ears go up before the bark the way you could at 4pm, and you cannot see what they are reacting to until it is close.
Be seen, and see your dog
Put a light or a reflective strip on your dog, not just on yourself. A dark-coated dog is close to invisible to traffic and to other walkers once the light has gone.
Wear something reflective yourself, even for a walk you have done a hundred times. Drivers and cyclists need the warning as much as your dog does.
Carry a small torch or use your phone's, and use it to check the ground and read your dog's body language rather than to light the whole street.
Keep the leash on and reasonably short in places you cannot see clearly: unlit stretches, blind corners, anywhere a person, a dog or a fox could appear without warning.
Choose the route on purpose
Walk routes your dog already knows well, rather than exploring somewhere new after dark. Familiar ground gives them less to startle at.
Prefer lit streets over the unlit park for the evening walk, even if the park is nicer, and save the park for daylight.
Shorten the walk rather than cutting it. A dull, well-lit 15 minutes beats a longer walk through territory your dog cannot read.
Put the longer, more interesting walk at the weekend, in daylight, and let the weekday evening walk be the plain one.
Let the nose do the work light cannot
Sniffing does not depend on seeing clearly, and a dog working a hedge line with their nose is a calmer dog than one scanning the dark for movement.
Let your dog sniff more than usual on the evening walk. It gives them something to do with attention that would otherwise go to every noise.
Practise recall in your own garden or on a familiar, well-lit street before you need it somewhere harder to see, since a dog you cannot see clearly is a dog you cannot call back with confidence.
Keep treats somewhere you can find them without a torch. Fumbling in the dark undoes the timing that makes a reward work.
When a startle is more than a startle
An occasional jump at a shape that turns out to be a bin bag is ordinary. A dog who is worried about most of the walk, or who stays jumpy well after the thing has passed, is telling you something bigger than the light.
Working below the point where your dog reacts is the condition for learning near something that unsettles them, so add distance rather than pushing past a stopped dog. If the wariness is broad rather than tied to a single dark stretch, read it alongside the second fear period rather than as a lighting problem on its own.
Safety note
Book a veterinary examination if the change was sudden, if your dog is reluctant to go out at all, or if the reactivity is new rather than a gradual adjustment to less light. Sudden behaviour change warrants a veterinary check, and pain frequently presents as a change in behaviour rather than as obvious lameness. Get help now if a startle has turned into growling, snapping or lunging at a person or another dog.
Today's version, in one line: light on your dog, leash shortened past the unlit stretch, and the familiar route rather than a new one.