The sun is the hottest from 11am to 2pm so if you avoid this window you'll be avoiding the hottest part of the day.
3. Keep their belly wet. If you absolutely must have your pup outside during the blazing mid-day sun, keep a bottle of cool water with you and regularly soak their belly and paws. These two areas are the quickest way for your pup to lose heat through induction (touch) which also makes them the quickest way for you to cool your pup down! If you're in a jam and your pup is heating up, get that belly soaked asap!
Remember to watch for warning signs: Your pup should pant a consistent rate when they're cooling their system under normal circumstances; and this is likely something you've seen many times and will easily recognize unless it's your first puppy. If your pup is panting rapidly or excessively or appears unfocused or confused this could be a sign of shock and you need to cool your pup down (not too quickly or you can make matters worse, just stay calm and soak their belly and paws, get them a cool drink and monitor their breathing closely to ensure they're improving). If the excessive panting doesn't subside, take them to your vet or an emergency after hours vet clinic asap to make sure they aren't suffering from heat stroke or exhaustion.
Stay cool, stay smart and enjoy your time outside this summer...it will be winter before you know it! Blurg!