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How Sniffout scores walk quality

When Sniffout shows you a green bar for 8am and an amber one for midday, that is not a guess. Each bar is calculated from real weather data using thresholds drawn from veterinary research - studies tracking hundreds of thousands of UK dogs, clinical data on heat-related illness, and welfare guidance published by the veterinary organisations that treat these conditions every year.

But it is guidance, not a verdict. The score reflects what the weather is likely to feel like for an average healthy adult dog of a typical breed. Your dog is not average. A French Bulldog and a Siberian Husky standing in the same sunshine are having completely different experiences. A dog recovering from illness, or an older dog with stiff joints, needs a different walk than the same dog in peak condition.

Use the scores as a starting point. They will remove the guesswork on most days. On the days where your dog seems off, or the weather is genuinely borderline, what you see and feel will always matter more than a number on a screen.

What we measure

Temperature is the biggest factor in walk quality for most dogs. Dogs cool themselves almost entirely through panting - a process that becomes progressively less effective as temperature and humidity rise. UK veterinary research has found that heatstroke in dogs occurs at lower temperatures than most owners expect: the median temperature on exercise-triggered heatstroke days in the UK is around 16-17 degrees Celsius, measured as Wet Bulb Globe Temperature (a composite measure incorporating humidity and solar radiation that reads lower than standard air temperature). This is UK-specific data from real clinical cases, not estimates from human physiology. BVA data shows that 38 percent of small animal vets had treated dogs for heatstroke after being walked on a hot day - compared to just 9 percent from hot cars. Walking, not confinement, is the primary cause of heatstroke in UK dogs. Because humidity affects how effectively panting works, Sniffout uses apparent temperature (the “feels like” figure that combines heat and humidity) rather than air temperature alone.

Rain is scored on what is actually falling, not just the chance of rain. A 90 percent chance of light drizzle is very different from a 50 percent chance of heavy downpour. Sniffout uses Met Office rain intensity classifications to separate light drizzle (no penalty - dogs are fine in drizzle) from moderate rain (shorter walk recommended) from heavy rain or thunderstorms (not recommended). Thunderstorms are treated as a hard stop - not because of lightning risk, but because dogs can panic, bolt, and become lost.

Wind matters most when walks involve woodland or exposed ground. Sniffout flags high wind conditions because falling branches and uprooted trees create genuine hazard in woodland at sustained winds of 50 km/h or above - the threshold used by outdoor education organisations to close woodland activities. For small dogs, moderate wind (around 30-40 km/h) can make walking uncomfortable and unstable before woodland risk becomes a factor.

Cold is scored differently by breed. Short-coated and small dogs start to struggle at around 7 degrees Celsius, while most medium-coated breeds are comfortable well below zero. Sniffout applies wind chill to the effective temperature rather than raw air temperature, because the combination of cold and wind extracts heat from a dog’s body significantly faster than either factor alone.

Breed adjustments are built into the scoring for brachycephalic breeds - French Bulldogs, Pugs, English Bulldogs, and similar short-muzzled dogs. These breeds have a restricted airway that makes panting less efficient, and peer-reviewed data shows they have significantly higher risk of heat-related illness than average dogs at the same temperature. Sniffout shifts all heat thresholds four degrees lower for these breeds. This offset is modelled from available evidence - including VetCompass data showing French Bulldogs have 6.5 times the heat-related illness risk of Labradors, and clinical data showing a Bulldog developed hyperthermia at 21 degrees Celsius while standing still - rather than a single published threshold.

Where our thresholds come from

The scoring thresholds are drawn from the following sources:

Veterinary research from the Royal Veterinary College’s VetCompass programme, which has tracked over 900,000 UK dogs under primary veterinary care and produced the most detailed UK-specific data on heat-related illness in dogs - including which breeds are most at risk and at what temperatures exercise-triggered illness occurs.

UK welfare guidance from the PDSA, Blue Cross, and RSPCA, whose published walking guidance provides the practical thresholds most commonly cited by UK vets and pet care organisations.

Veterinary clinical data on heatstroke in dogs published in Veterinary Sciences and Scientific Reports - peer-reviewed studies producing the breed risk multipliers used in the brachycephalic adjustment (French Bulldogs have 6.5 times the heat-related illness risk of a Labrador; Bulldogs have nearly 14 times the risk).

Met Office weather classification standards for rain intensity - the same framework used by UK weather forecasters and hydrologists.

Beaufort wind scale thresholds used by outdoor education organisations to make decisions about woodland activities.

Vets Now temperature guidance for cold weather walking, which provides the breed-specific cold thresholds used in the low-temperature scoring.

What we estimate

Not everything in the scoring system comes from published research, and we think it matters to say so clearly.

Humidity multipliers. The scoring applies a 1.3x multiplier to heat penalties at relative humidity above 60 percent, and a 1.6x multiplier above 80 percent. The 80 percent threshold has veterinary research behind it - above that level, panting stops working effectively. But the 1.3x and 1.6x multiplier values, and the 60 percent intermediate threshold, are our estimates based on veterinary physiology principles. They are not derived from specific published research. We applied them because ignoring humidity at temperatures above 22 degrees Celsius would understate the risk, but we cannot point to a study that verifies these exact numbers.

Mud risk thresholds. The dry/damp/muddy/very muddy indicators are based on 48-hour cumulative rainfall and soil drainage research, not published dog walking guidance. No veterinary source publishes specific rainfall thresholds for path conditions. Our thresholds are practical estimates informed by soil science.

Small dog wind sensitivity. The specific wind speeds at which small dogs become unstable (around 32-40 km/h) come from aggregated sources rather than a single authoritative study. The principle is well-grounded - small dogs have a higher surface area to body weight ratio and are physically lighter - but the exact kilometre-per-hour thresholds are our interpretation.

We would rather be honest about what we know and what we estimate than present everything as settled science. The estimates are conservative - they err on the side of caution - and they will be updated as better data becomes available.

Breed-specific adjustments

The app adjusts scoring thresholds for the breed profile you set. The most significant adjustment applies to brachycephalic breeds (French Bulldogs, Pugs, English Bulldogs, Shih Tzus, and Cavalier King Charles Spaniels). VetCompass data shows these breeds have 2 to 14 times higher risk of heat-related illness than average dogs at equivalent temperatures and exercise levels. Sniffout shifts heat scoring thresholds four degrees lower for these breeds - so a day that scores as “good” for a Labrador may score as “fair” for a French Bulldog.

Disclaimer

Sniffout’s walk quality scores are based on published veterinary research and UK weather data. They are intended as general guidance only and are not a substitute for veterinary advice. Every dog is different - breed, age, weight, health conditions, fitness level, and individual temperament all affect how your dog responds to weather conditions. Always watch your dog for signs of discomfort, overheating, or distress during walks. If you are concerned about your dog’s health or exercise tolerance, consult your vet. Sniffout does not accept liability for any injury or illness arising from use of the walk quality scoring system.

Sources

Peer-reviewed research

UK veterinary organisations

Weather and environmental