Keep Apple Watch within acceptable operating temperatures
Learn about suitable operating conditions for Apple Watch, and get tips for maintaining those temperatures and handling your device safely.
Find recommended temperatures and conditions below for most Apple Watch models or for Apple Watch Ultra. Apple Watch Ultra and later are designed for use in conditions and situations beyond what's recommended for other Apple Watch models.
Recommended conditions for using and storing most Apple Watch models
Apple Watch is designed to work best in ambient temperatures between 32° to 95° F (0° and 35° C).
You can store your Apple Watch in ambient temperatures between -4° and 113° F (-20° and 45° C).
Recommended conditions for using and storing Apple Watch Ultra
Apple Watch Ultra and later work best in the following conditions:
Ambient temperature while you're wearing Apple Watch Ultra: -4° to 130° F (-20° to 55° C)
Ambient temperature while Apple Watch Ultra is charging: 32° to 95° F (0° to 35° C)
Ambient temperature when Apple Watch Ultra is being stored: -4° to 113° F (-20° to 45° C)
Water temperature during underwater activities with Apple Watch Ultra: 32° to 104° F (0° to 40° C)
Relative humidity: 5% to 90%, noncondensing
Ambient temperature and other conditions can affect some features on Apple Watch Ultra and later, and other Apple Watch models. For example, your battery might not last as long in cold temperatures. The ECG app is accurate only when used in ambient temperatures from 32° to 95° F (0° to 35° C). Heart rate measurements can be less accurate in low ambient temperatures. And in very low ambient temperatures, or in conditions where the temperature changes rapidly, the touch screen on your Apple Watch might not respond as expected.
Apple Watch temperature management
Apple Watch shouldn’t sit unattended in direct sun for long periods or be left in places like a car on hot days. Storing and using your device outside of the recommended temperature range could shorten its battery life or cause other damage.
If necessary, Apple Watch will regulate its internal temperature. If this happens, you might notice:
Charging times might increase, or charging might stop.
The display might dim.
Data transfers could pause or slow down.
Apps might close.
On cellular models of Apple Watch, you might not have a cellular connection or you might not be able to make or receive calls. When this happens, the cellular button in Control Center appears red. Normal cellular functionality resumes after Apple Watch cools. However, you can still make emergency calls.
If your Apple Watch gets too hot
If your Apple Watch experiences above-normal temperatures, it displays only a red thermometer and the time. Here's what to do:
If you're wearing your device, remove it from your wrist. If your Apple Watch is in the process of charging, remove it from its charger. Your watch turns off a few seconds after displaying the thermometer. If you leave your watch on the charger, your watch won't turn off. If you try to turn your watch back on, the red thermometer will appear again.
Move your Apple Watch to a cooler place and let it cool down before putting it back on or continuing to charge it. When your watch cools down, it turns back on.
If you're making cellular calls on a cellular model of Apple Watch in an area with a weak cellular signal, move to a location with a stronger signal.
Handle your Apple Watch and its accessories safely
Apple Watch, its power adapter, and Apple Watch Magnetic Charging Cable follow applicable surface-temperature standards and limits. Even within these limits, sustained contact with warm surfaces for long periods of time might cause discomfort or injury.
Here are some safety tips:
Be aware that Apple Watch, its power adapter, and Apple Watch Magnetic Charging Cable warm up when plugged in to a power source.
If plugged in, Apple Watch, Apple Watch Magnetic Charging Cables, and power adapters shouldn't be in prolonged contact with skin.
While charging, Apple Watch, its power adapter, and Apple Watch Magnetic Charging Cable should stay in a well-ventilated area. For example, if these devices are charging or plugged in to power sources, they shouldn't be covered.
Use of cellular data on Apple Watch cellular models may make the device feel warm.
Take off your Apple Watch if it becomes uncomfortably warm. Take special care if you have a physical condition that affects your ability to sense heat against the body.
Apple Watch, its adapter, and Apple Watch Magnetic Charging Cable meet the standard for Safety of Information Technology Equipment, IEC 60950-1:2005+A1:2009+A2:2013. Many countries and regions have adopted this safety standard. For example, it’s referred to as:
UL 60950-1 in the United States
CSA 60950-01 in Canada
EN 60950- in Europe
AS/NZS 60950:1 in Australia and New Zealand