
Summer is great.
Higher blood sugars because it’s 30°C outside?
Not so fun.
One thing I’ve noticed over the years is that hot weather seems to affect my diabetes in ways I don’t always expect.
Sometimes my blood sugar drops more quickly.
Other times it runs higher than usual.
Add in sweating, dehydration and trying to keep insulin cool, and summer can become surprisingly challenging.
Here’s what I’ve learned about managing Type 1 diabetes during hot weather and what the research says.
Does Heat Affect Blood Sugar?
The short answer is yes, it can.
Hot weather doesn’t affect everyone in exactly the same way, but it can influence:
- insulin absorption
- hydration
- activity levels
- insulin storage
- appetite
This means your usual routine may not work exactly the same on a very hot day.
Dehydration Can Raise Blood Sugar
One of the biggest issues during hot weather is dehydration.
When you don’t drink enough fluids, glucose becomes more concentrated in your bloodstream.
This can contribute to higher blood sugar readings.
I’ve found that simply carrying a water bottle more often during the summer is one of the easiest habits to build.
Related reading:
Blog – 7 Small Things That Quietly Raise Blood Sugar
Heat May Make Insulin Work Faster
Many people with Type 1 diabetes notice insulin seems to absorb more quickly during warm weather.
That doesn’t happen every time, but it’s something I keep in mind if I’m spending the day outside.
It’s another reminder to keep an eye on trends rather than assuming every day will behave the same.

Exercise Changes Things Even More
Summer usually means:
- more walking
- holidays
- days at the beach
- gardening
- playing with the kids
All that extra movement can affect blood sugar alongside the heat itself.
Related reading:
Blog – Why Walking After Meals Can Help Blood Sugar Levels
Don’t Forget Your Insulin
Insulin should be stored according to the manufacturer’s recommendations.
Leaving it in direct sunlight or a hot car can affect its quality.
If you’re travelling, an insulated medication case can be a simple way to help protect it.
Related reading:
Blog – My Type 1 Diabetes Travel Checklist
Looking After Your CGM
Hot weather often means more sweating.
I’ve found that overpatches can help keep my Libre sensor secure during holidays and warmer days.
Related reading:
Blog – Best CGM Patches That Actually Stay On
What Helps Me During Hot Weather?
I try to keep things simple:
- Drink water regularly.
- Keep hypo snacks nearby.
- Check my Libre trends a little more often.
- Keep insulin out of direct heat.
- Accept that some days will be less predictable than others.
Products That May Help
Ideal for holidays and hot weather.
Insulated Reusable Water Bottle
Makes it easier to stay hydrated throughout the day.
Useful for keeping sensors secure during sweaty summer days.
Frequently Asked Questions
Can hot weather raise blood sugar?
Yes. Heat, dehydration and changes in activity can all affect blood sugar levels.
Can heat make insulin work faster?
Some people find that insulin absorbs more quickly in warm weather, although responses vary.
How should insulin be stored in summer?
Follow the manufacturer’s storage instructions and avoid exposing insulin to excessive heat or direct sunlight.

Can sweating make Libre sensors fall off?
Sweating may reduce adhesion, which is why many people choose to use overpatches during hot weather.
Final Thoughts
Summer should be about enjoying the longer days, not constantly worrying about your blood sugar.
I’ve learned that a little extra planning goes a long way.
Staying hydrated, protecting my insulin and keeping an eye on my Libre has helped me feel much more confident during hot weather.
Like most things with Type 1 diabetes, it’s less about being perfect and more about understanding how your body responds.
Disclaimer
This is based on my personal experience living with Type 1 diabetes. Always consult your healthcare professional before making changes to your diabetes management.
This blog contains affiliate links which means I may earn a small commission if you make a purchase at no extra cost to you.
This article is based on my personal experience living with Type 1 diabetes. Always consult your healthcare professional before making changes to your routine.
