5 Unexpected Rainy Day Dangers for Dogs

Katie Grzyb, DVM
By Katie Grzyb, DVM on Mar. 1, 2023
small black and white shih tzu on a walk in the rain

Storms can put a damper on anyone’s day, even for our canine companions. The rainy weather leads to wet walks, decreased exercise, and no outdoor playtime. But it’s not just that our dogs get damp—rainstorms can also lead to unforeseen dangers and issues for our four-legged friends.

Here’s what pet parents need to be aware of when taking their pup out in the rain, and why it’s important to shorten playtime and walks during inclement weather.

1. Low Visibility, Lightning, and Thunder

Rainstorms often bring fog, downpours, thunder, and lightning—all of which lead to decreased visibility and sudden, unexpected noise. Loud claps of thunder can spook many pooches, causing them to react and run away. This can lead to missing dogs and accidents, because cars have difficulty seeing through the inclement weather. It can be a deadly combination.    

Thunder can cause dogs a great deal of anxiety. This stress can cause pets to hurt themselves as they try to chew or scratch their way into or out of rooms and crates (a common thunder phobia response). It’s important to discuss possible storm phobias with your primary care veterinarian, as there are many great options (both holistic and medication) to help calm dogs in storms.   

Lightning strikes are also possible, though rare, and are usually fatal. Always avoid long walks during rainstorms, as lightning is attracted to metal (including umbrellas). 

2. Puddles

Most dogs love to play in rain puddles. Unfortunately, these puddles can contain harmful bacteria and toxins.


The most common bacteria found in stagnant water is leptospirosis, which is transmitted through rodent urine. Rodents often bathe in rain puddles, leaving the bacteria behind. The bacteria then enter a dog’s (or human’s) body through uncovered wounds or through ingestion, leading to liver and kidney failure. If untreated, this condition is fatal.

The good news is that there is a vaccination that can be added to the DAPP series to protect against this infection. Discuss this vaccine series with your veterinarian if your dog is frequently drinking out of rain puddles or swims in lakes. 


Another common inhabitant of puddles is giardia. This is a microscopic parasite that, if ingested, may cause:

Medication such as metronidazole or fenbendazole can be used to kill this infection, but it can be difficult to clear from young and/or immunocompromised dogs.  

Various Toxins

Certain toxins such as pesticides and ethylene glycol (antifreeze) can be washed into rain puddles and lead to severe effects in dogs. These can range from gastrointestinal issues to kidney failure to death.

If there are any lingering puddles from a recent (or ongoing) rainstorm, keep your dog away from them to avoid any risks of contaminated water. Protect your dog’s paws by training them to wear rain boots, or wash and dry their paws as soon as you get home using unscented Dawn dish soap, baby wipes, or paw wipes.

3. Mushrooms

Mushrooms are a type of fungi that thrive in moist environments. While not all mushrooms are toxic when ingested, many varieties can be severely poisonous—and it can be difficult to know which mushrooms are edible and which are toxic.

Treat every mushroom ingestion as a possible toxicity, and monitor your dog vigilantly during walks to avoid mushroom ingestion.

Clinical signs of mushroom poisoning in dogs include:

These signs are dependent on the type of mushroom ingested and the amount ingested, and they can occur within minutes to hours. Mushrooms tend to grow in wooded areas during the spring and early fall, but in warmer climates they can grow year-round.  

If you’re concerned that your dog may have ingested a mushroom, try to get as much out of your dog’s mouth as possible. Then call your veterinarian immediately to find out next steps for your pup. Your vet will most likely advise you to come in to treat any possible toxin ingestion.

It’s very important to obtain a sample of the mushroom and to note where it was found, as these can help your vet determine the type of mushroom ingested. Place a sample of the mushroom on a white sheet of paper, wrap it in wax or parchment paper, place it inside a Ziploc bag, and keep it refrigerated until it can be examined by the vet.

4. Toads and Frogs

Along with mushrooms, rain tends to bring out toads and frogs. Most types of toads are nontoxic if ingested by a dog; however, most toads do produce some sort of toxin, although most emit small amounts and are considered nontoxic. 

But there is one type of toad, called the Bufo toad, that contains a toxin within their parotid glands that’s detrimental to dogs. The two most important species of Bufo toads known for toxic effects in dogs are:

  • Bufo alvarius (aka the Colorado River toad or the Sonoran Desert toad), found in Southern Arizona, Southern California, and Southern New Mexico

  • Bufo marinus (aka the marine toad, the cane toad, or the giant toad), found in Florida, Hawaii, and Southern Texas

This Bufo toxin is a toad’s defense mechanism, and when the toad is disturbed by a dog, parotid glands release a thick, white liquid that can enter the dog’s eyes, nose, or mouth. Clinical effects range from mild, local irritation in areas where the toxin touched to severe, systemic disease and even death. If you believe your dog was poisoned by a toad (no matter the type), contact your veterinarian immediately.

5. Pneumonia

Exposure to cold and wet weather for long periods of time can lead to inflammation in the respiratory tract. This inflammation makes dogs more prone to bacteria invasion of the airways—aka, pneumonia. This is a higher risk for young dogs, older dogs with other systemic diseases, and any immunocompromised dog. 

It’s important to dry off your dog with a towel as soon as you come in from rainy walks and give them a warm, dry area to stay in. You may also consider training your pooch to wear a raincoat to avoid exposure to wet weather.

Clinical signs of pneumonia in dogs include:

  • Lethargy

  • Nasal discharge

  • Eye discharge

  • Coughing

  • Wheezing

  • Decreased appetite

  • Fever

  • Trouble breathing (if the lungs are severely affected)

If you notice any of these signs, bring your dog to the veterinarian for evaluation right away. Pneumonia can be fatal if left untreated. 

Though there are many concerning events that can occur during rainy days, dogs still need their exercise—even in the face of stormy weather. Try to limit playtime to inside during inclement weather. When you must take your dog out, always monitor your pet closely to stop them from drinking out of puddles, eating plants, or finding toads to lick. Prevention is much more effective than dealing with rain-induced issues later. 

Featured Image: iStock/SolStock

Katie Grzyb, DVM


Katie Grzyb, DVM


Dr. Katie Grzyb received her Doctorate of Veterinary Medicine from Ross University in 2009. She continued her clinical training at...

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