Preparing for a heatwave
What matters most in a heatwave, what official guidance in the UK 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. Stay in the shade between 11am and 3pm, when UV is strongest.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 cut.
What official guidance in the UK says
- Stay in the shade between 11am and 3pm, when UV is strongest.1
- Close blinds and curtains on sunny windows during the day to keep your home cool.1
- UKHSA says electric fans are useful only when the air is below 35°C.1
- Check on people at higher risk from the heat.2
- Heat exhaustion usually needs no emergency help if the person cools down within 30 minutes.3
Stay safe
Water and food for a few days
For two adults, SupKit's figures for 3 days are:
| 3 days | |
|---|---|
| Drinking water | 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:
- Tinned chilli
- Tinned soup
- Baked beans
- Microwave rice pouch
- Tinned tuna
- Crackers
- Peanut butter
- Dried fruit and nuts
- Cereal bars
- Tinned 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 |
|---|---|---|
| Tinned chilli | varies by recipe | check the label |
| Tinned 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 |
| Tinned 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 |
| Cereal bars | varies by recipe | vegetarian |
| Tinned 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.
- UK food law names 14 major allergens, including cereals containing gluten, milk, eggs, fish, peanuts, tree nuts, soya, sesame, celery, mustard and sulphites.4
- On pre-packed food in the UK, these allergens must be emphasised in the ingredients list, for example in bold.4
- 'May contain' warnings aren't a legal requirement, so a missing warning doesn't guarantee a food is free of an allergen.4
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?
Dial 999 if you think someone has heatstroke.
Sources
- Beat the heat: staying safe in hot weather, UK Health Security Agency (GOV.UK). Checked 28 October 2026. Contains public sector information licensed under the Open Government Licence v3.0.
- Heatwave: how to cope in hot weather, NHS. Checked 28 October 2026.
- Heat exhaustion and heatstroke, NHS. Checked 28 October 2026.
- Food allergy and intolerance advice for consumers, Food Standards Agency (GOV.UK). Checked 28 October 2026. Contains public sector information licensed under the Open Government Licence v3.0.
- Foods to avoid giving babies and young children, NHS. Checked 28 October 2026.
We summarise official guidance in our own words. Always follow advice from your local authorities.
