The weather can have a significant impact on people with diabetes as blood glucose levels can be affected in hot and cold weather.

In hot weather, the risk of hypoglycemia and hyperglycemia is increased, while people with diabetes tend to have higher HbA1c levels during the winter months.

Diabetes and hot weather

Hot weather can cause several problems cause for people with diabetes. These include:

  • Increased hypo and hyper risks
  • Dehydration
  • Carrying medication
  • Blood testing
  • Heat exhaustion

Increased hypo and hyper risks

Hot weather can increase the risk of hypos and hypers for people on blood-glucose lowering medication. Whether it is a blood glucose raising or lowering effect can vary from person to person.

According to the Joslin Diabetes Center, the body’s metabolism is higher in hot weather, and this can increase the absorption of medication such as insulin.

Increased activity in hot weather can exacerbate this risk, and you should test your blood sugar more often if taking part in exercise or physical activity.

You may also need to adjust your insulin levels in hot weather, especially if you are experiencing erratic blood sugar levels. This should be discussed with a member of your health care team.

Hypos might be harder to spot in hot weather, and you should take extra care to prevent hypos from occurring. Steps that can be made include:

  • Don’t disregard hypo symptoms – sweating and fatigue, which can occur in hot weather, could be signs of a hypo
  • Take extra care when driving – test your blood before and after each journey, and stop regularly on longer journeys
  • Keep sugar on hand at all times – such as glucose tablets, or some quick-acting carbohydrate


Hot weather can increase the risk of dehydration, and so can having higher than normal blood sugar levels. Ensure you’re drinking fluid regularly during warmer weather, and particularly if your sugar levels are high.

If you feel dehydrated, drink water and test your blood sugar to see if your sugar levels are high.

Carrying medication

As certain medical supplies need to be kept cool, such as insulin, hot weather can be problem. Be sure to keep medication out of direct sunlight, and use cooling pouches if you take medication out with you.

Blood testing

Extreme temperatures can cause damage to testing strips, and exposure to humidity can affect their accuracy, or stop them working. Blood testing strips should be stored at room temperature and kept away from direct sunlight.

Heat exhaustion

People with diabetes have a higher risk of heat exhaustion, which is considered a medical emergency. This can be avoided by resting and drinking more water than normal.

Symptoms of heat exhaustion include:

  • Clammy skin
  • Sweating more than usual
  • Headaches
  • Dizziness
  • Fast heartbeat
  • Nausea

Diabetes and cold weather

Your blood sugar levels may be higher during the winter, and not necessarily due to anything you are doing differently.

Wen Wei Liang, MA concluded that diabetic patients had higher HbA1c values in the winter and lower levels in the summer, which was backed up in a study by CL Tseng et al, who reviewed variations in HbA1c values of 285,705 veterans with diabetes.

There are a number of things you can do to keep your blood sugar under control during cold weather, including:

  • Keep testing your blood
  • Keep your activity levels up
  • Keep monitoring your diet
  • Keep illness out in the cold

Keep testing your blood

Regular testing will help you catch any highs, and ascertain if they can be attributed to a specific part of your diabetes management.

However, testing can be harder in cold weather. If your hands are cold, it can be trickier to draw blood, so you may want to warm your hands up before doing a test.

Keep your activity levels up

Not only can exercise keep you warm in cold weather, but it can increase insulin sensitivity, which helps the body to better regulate blood sugar levels. Bear in mind, though, that exercise can affect blood glucose for up 48 hours, and you may need to test regularly to prevent any hypos if your medication can cause them.

Keep monitoring your diet

When it’s colder, people may become more tempted to snack on “comfort foods”, or order more takeaways. This is due to the body’s natural response to seek more calories to fight against the weather during the colder months

It is important to be vigilant in limiting ready meals and processed snacks, which can leave you hungry again shortly afterwards. Instead, eat more natural foods or snacks such as fruits and nuts, and stick to home cooked meals that you can prepare yourself.

Be sure to keep an eye on your carbohydrate content, as carbohydrate has a big impact on blood glucose levels.

Keep illness out in the cold

Colds and viruses are spread around more frequently in cold weather, and these can make blood sugar levels higher than normal and harder to control.

Things you can do to prevent illnesses developing include keeping warm, eating healthily, testing regularly and also ensuring you have had your annual flu jab.