Preparing for a heatwave
What matters most in a heatwave, what official guidance in the US says, and long-life food that suits it.
In a heatwave, the things that matter most are drinking water, essential medication, emergency contacts, first aid kit. Never leave people or pets in a closed car on a warm day.1
What matters most
- Drinking water Essential
3 litres per person per day for drinking is the commonly recommended amount. - Essential medication Essential
A supply of any medication your household relies on. - Emergency contacts Essential
Important numbers saved where you can reach them without the internet. - First aid kit Essential
A stocked first aid kit that everyone knows where to find. - Water for pets Essential
An estimate based on each pet's species and size. - Plan for medication that needs a fridge Essential
Know how you'd keep it cool during a power outage.
What official guidance in the US says
- Never leave people or pets in a closed car on a warm day.1
- Don't rely on a fan as your main way to keep cool; find a cooling centre if you have no air conditioning.1
Stay safe
Water and food for a few days
For two adults, SupKit's figures for 3 days are:
| 3 days | |
|---|---|
| Drinking water | 4.8 gallons (18 L) |
| Food energy | 13,500 calories |
Long-life food that suits a heatwave
Each of these keeps without a fridge and doesn't need the fridge once opened:
- Canned chili
- Canned soup
- Baked beans
- Microwave rice pouch
- Canned tuna
- Crackers
- Peanut butter
- Dried fruit and nuts
- Granola bars
- Canned fruit
Allergies, dietary needs and children
Plan around everyone at home: allergies, intolerances and diets come first, and familiar food matters most for children. Recipes vary between brands, so always read the label of the product you buy.
| Food | Typical allergens | Typically suitable for |
|---|---|---|
| Canned chili | varies by recipe | check the label |
| Canned soup | varies by recipe | vegetarian |
| Baked beans | none of the main allergens in its main ingredient | vegan |
| Microwave rice pouch 250g | none of the main allergens in its main ingredient | vegan |
| Canned tuna | fish | check the label |
| Crackers | cereals containing gluten | vegan |
| Peanut butter | peanuts | vegan, gluten free |
| Dried fruit and nuts | tree nuts | vegan, gluten free |
| Granola bars | varies by recipe | vegetarian |
| Canned fruit | none of the main allergens in its main ingredient | vegan, gluten free |
Typical allergens and diets are SupKit's guide to the main ingredient, not a product's label.
- US law names nine major food allergens: milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, soybeans and sesame (sesame added from 2023).2
- Labels must name each major allergen's source, either in brackets in the ingredient list or in a 'Contains' statement next to it.2
- 'May contain' warnings are voluntary in the US, so not every maker uses them and their absence is not a guarantee.3
Young children
Questions
What do I need for a heatwave?
Drinking water, Essential medication, Emergency contacts, First aid kit, Water for pets, Plan for medication that needs a fridge.
How do I stay safe in a heatwave?
Heatstroke signs include body temperature above 103°F (39.4°C) and red, hot, dry skin.
Sources
- Extreme Heat, Ready.gov (US DHS / FEMA). Checked 28 October 2026.
- Food Allergies: What You Need to Know, U.S. Food and Drug Administration. Checked 28 October 2026.
- Have Food Allergies? Read the Label, U.S. Food and Drug Administration. Checked 28 October 2026.
- Choking Hazards | Infant and Toddler Nutrition, Centers for Disease Control and Prevention. Checked 28 October 2026.
- Foods and Drinks to Avoid or Limit | Infant and Toddler Nutrition, Centers for Disease Control and Prevention. Checked 28 October 2026.
We summarise official guidance in our own words. Always follow advice from your local authorities.
