Weather could be affecting your diabetic dog’s blood sugar

The answer? Yes — indirectly, but significantly.

Here’s what we found out about how temperature, weather changes, and seasonal shifts that can affect your diabetic dog, and how you can stay ahead of it.

Cold weather and high blood sugar

Cold months often mean:

• Less outdoor activity
• More stress (from cold or storms)
• Changes in how insulin absorbs
  

When dogs are less active during winter, their bodies may use less glucose, which can cause blood sugar levels to rise. In addition, stress from cold exposure or snowstorms can release hormones like cortisol, which naturally raises blood glucose.

Also, injecting insulin into cold skin or fat may slow down absorption, meaning the insulin takes longer to work — leading to higher post-meal numbers.

We noticed this with our diabetic border terrier Parker. We live in Ottawa, Canada and have very cold winters with some days below -30 celsius.

Tips for managing in cold weather:

• Keep insulin and your dog’s body warm at injection time
• Maintain indoor exercise routines
• Track blood glucose trends. Like Parker, your dog may need slight insulin adjustments in winter
  

Hot weather and hypoglycemia

Summer brings its own set of challenges. In warm weather, many dogs:

• Are more active outdoors
• Eat less
• Absorb insulin more quickly
  

When insulin works faster (due to increased blood flow in the heat) and your dog is burning more energy through play, their blood sugar can drop too low, leading to hypoglycemia.

Dehydration also plays a role as it can stress your dog’s system and affect how their body processes insulin and nutrients.

We also get warm, humid summers in our part of the world and have seen some of these issues with Parker. He’s surprised us with low readings on very hot days.

Watch for signs of low blood sugar:

• Lethargy or weakness
• Wobbliness or unsteady walking
• Glazed eyes or sudden disinterest

Could Seasonal Allergies Be Affecting Your Diabetic Dog Too?

One thing we've noticed with Parker every spring is seasonal allergies. Like many dogs, he starts sneezing more, rubbing his face, and generally looking a little uncomfortable when pollen levels rise.

Under the guidance of our veterinarian, we've occasionally used human allergy medications to help manage his symptoms. While they seemed to help with the sneezing, we began to wonder whether they were affecting his energy levels or even indirectly influencing his blood glucose management.

So, as careful dog owners tend to do, we ran a little experiment.

For two weeks, we stopped giving Parker his allergy medication (again, with our veterinarian's knowledge). The sneezing gradually returned, but something else changed too. He seemed to have more energy on our walks and was more enthusiastic about being active.

This isn't scientific proof that the medication was affecting him, and every dog responds differently. However, it was a good reminder that seasonal changes don't just mean warmer temperatures or different exercise routines. Spring can also bring allergies, medications, changes in energy levels, and other factors that may indirectly affect a diabetic dog's daily routine.

If your diabetic dog seems different during allergy season, it's worth discussing with your veterinarian. Keep notes in your diabetes journal about allergy symptoms, medications, activity levels, appetite, and blood glucose readings. Over time, you may spot patterns that help you better understand how the changing seasons affect your dog.

Tips we've learned for managing in the heat:

Avoid midday walks — stick to early mornings or evenings

Keep your dog hydrated (add ice cubes or low-sodium broth to water if needed)

Never give insulin on an empty stomach — make sure your dog eats first

Storms, stress and glucose spikes

Many dogs are sensitive to:

• Thunderstorms
• High winds
• Sudden drops in barometric pressure
  

These can all trigger stress, which may lead to temporary spikes in blood glucose. If your dog’s numbers seem erratic during stormy weeks, weather-related stress could be to blame. Parker seems to have unpredictable blood glucose readings on days with high winds. I don't know if it's the sound of the wind, more smells travelling through the air, or something else, but it can make it BG numbers go lower.

Things we've had success with:

Use calming aids like Thundershirts, white noise, or pheromone sprays

Give your dog a cozy, safe space to hide during storms

Monitor glucose levels closely if your dog is weather-sensitive

Keep a weather and glucose log

If you’re noticing fluctuations in your dog’s readings, consider tracking:

• Daily weather (temperature, storm activity)
• Activity levels
• Appetite
• Water intake
• Blood glucose readings
  

A simple log can help you and your vet spot patterns and adjust insulin dosages seasonally.

What we've learned

While weather doesn’t directly change your dog’s blood sugar, it shapes everything around it — activity levels, stress, hydration, and insulin effectiveness.

Understanding how your dog responds to different conditions can help you stay one step ahead and avoid dangerous highs or lows.

Your dog’s diabetes journey is uniquely theirs. And yours. Staying informed, observant, and flexible through the seasons is one more way to give them the happiest, healthiest life possible.