Why does my phone say it needs to cool down?

What causes phones to overheat?

There are several potential reasons why your phone may get hot and display a warning that it needs to cool down:

Intensive app usage

Using resource-intensive apps like games, video editors, or navigation apps can heat up your phone’s processor and cause overheating. The more graphics, videos, or other processing power an app requires, the hotter your phone may get. Playing games or streaming videos for extended periods can easily overwork your phone’s CPU and raise its temperature.


Charging your phone, especially while using it or charging it rapidly, generates heat that can warm up the battery and other components. Using fast chargers that supply more power than your phone is designed for can make this effect even more pronounced. Charging while your phone is already hot from use compounds this temperature rise.

Bright display settings

Your phone’s display produces a significant amount of light and heat. Using maximum brightness, especially over long periods, can contribute to overheating your phone’s display and internals. This effect is worse if your phone is already warm from other usage.

Direct sunlight

Leaving your phone in direct sunlight, like on a car dashboard on a hot, sunny day, can quickly raise its external temperature and make its internals heat up significantly. The metals and plastics that make up your phone easily absorb and conduct heat. Direct radiation from the sun can make your phone’s temperature rise rapidly.

Poor signal

When your phone has a weak network connection, it has to work harder to maintain reception. Your phone emits stronger radio signals to reach the network, and processing these weak incoming signals also demands more effort. This extra work generates additional heat inside your phone.

Background apps and updates

Apps running in the background, using mobile data, or updating themselves can make your phone work harder, even while idle. If you have a lot of apps syncing data in the background, your phone has to continuously receive and transmit small amounts of data that build up heat over time. Overnight updates also cause your phone to run warmer while downloading and installing.

Damaged battery

If your phone battery is old, worn out, or damaged, it may no longer be able to handle heat as well. Batteries produce heat during charging and discharging. A battery in poor condition usually runs warmer and may cause your phone’s temperature to rise higher than normal. Faulty batteries can also misbehave and contribute excess heat inside your phone.

Nearby heat sources

External sources of heat like leaving your phone on a warm surface, near a heater vent, or other hot object can warm up your phone beyond safe levels, even if the phone isn’t being used. The metals and plastics that make up your phone conduct and retain heat readily.

Case or cover

Using a tight-fitting case or cover on your phone can trap heat produced during normal use inside your phone instead of allowing it to dissipate into the air. Using a phone case is important for protecting your phone, but a case that fits too tightly or is made from insulating materials can contribute to overheating over time.

How does my phone detect overheating?

Modern smartphones contain multiple temperature sensors to monitor conditions that could potentially damage components. Here are some ways phones detect overheating:

CPU temperature sensors

The processor or CPU inside a phone contains built-in sensors that track its temperature. If the CPU exceeds safe operating temperatures, it can reduce performance or even shut down parts of the system to prevent permanent damage. The phone uses these sensors to monitor CPU heat.

Battery temperature sensors

Lithium-ion batteries like those used in smartphones contain safety systems that prevent the battery from getting too hot. If the battery’s internal temperature sensor detects overheating, it can cut off charging or disable discharging to cool back down. The phone uses data from this sensor to monitor battery temperature.

Ambient temperature sensor

This sensor tracks the general internal temperature inside the body of the phone. A rise in ambient temperature indicates the phone’s internals are heating up overall, which usually correlates with processor and battery heat. The ambient sensor provides a general measure of internal heat.

Skin temperature sensor

This sensor measures the external temperature of the phone’s body right under the display/glass surface. A high skin temperature signifies the phone’s externals are getting hot, often due to intense internal heat dissipating through to the body. It provides a proxy for internal phone temperature.

Thermal throttling

Phones may deliberately throttle down CPU speed, screen brightness, charging speed, and other power draw if components reach unsafe temperatures. This lessens heat generation to prevent damage while allowing limited functionality. The phone throttles components based on feedback from its temperature and power sensors.

Machine learning

In addition to physical temperature sensors, phones may also use software and machine learning to model expected temperatures under different usage conditions. The software combines sensor readings with usage patterns to predictively identify abnormal overheating before it happens.

What happens when my phone overheats?

When a phone overheats beyond safe limits, either from external conditions or internal heat generation, several protection mechanisms may activate:

Performance throttling

The phone may forcibly reduce CPU speed, display brightness, and GPU performance to cut power draw and heat generation. It disables features like fast charging. You may notice lagginess and slowdowns as it throttles. This lessens the load on components while allowing basic usage.

Features disabled

The phone may turn off certain features entirely like 5G, WiFi, GPS, raise to wake, always-on display, vibrations, and haptic feedback. Any components that produce excess heat are powered down or disabled until temperatures decrease. This reduces nonessential sources of heat.

Charging paused

During periods of extreme overheating, the phone may stop battery charging entirely until it cools down. This prevents the heat from charging from exacerbating the phone’s high temperatures. It resumes charging normally once the phone cools back to safe levels.

Partial or full shutdown

If overheating cannot be controlled via throttling, the phone may engage in a partial or full shutdown of the system. It may disable everything except emergency calls or shut down completely until it cools off adequately. This prevents catastrophic damage from excessive heat.

Warnings displayed

The phone will display warnings about overheating, advising you to close apps, reduce usage, disable features like 5G, and/or move the phone to a cooler location. Warnings serve as an urgent notice to mitigate heating before hardware damage sets in.

Emergency calls only

During partial system shutdowns, the phone may enter an “emergency calls only” mode where only the cellular radio remains active for 911 calling. All other features get disabled to prevent heat damage until the temperature drops sufficiently. This maintains safety.

What should I do if my phone overheats?

If your phone displays an overheating warning or experiences shutdowns, lag, or other issues, follow these tips:

Stop phone usage

Quit resource-intensive apps, games, videos, and activities on your phone immediately to stop generating additional heat. Even basic usage can prolong overheating when the phone is already too hot. Avoid using it at all until it cools down.

Remove case

Take off any phone case or protective cover to prevent trapping heat. Cases can act as insulation and prevent heat dissipation. Let the bare phone radiate heat openly into the air and surrounding environment.

Move to a cooler place

Position the phone somewhere cool like an air conditioned room, in front of a fan, or even a refrigerator. The cooler the air temperature, the faster your phone can shed heat and recover to normal temperatures.

Turn off fast charging

Disable fast charging in your phone’s settings while it recovers from overheating. Fast charging generates additional heat that can prolong or exacerbate overheating issues. Use slower 5W or 10W chargers until the problem resolves.

Avoid direct sunlight

Keep your phone shaded and out of sunlight. The hot rays of the sun can quickly spike temperatures, especially if your phone is already warm. Interior pockets or purses work better than exterior pockets during overheating.

Power down and wait

Fully power off and leave your phone off for 30 minutes or longer to allow proper cooling. Extended powered off rest gives temperatures time to fully normalize before turning it back on. This avoids restarting while still overheated.

Check apps

Some apps misbehave with battery or cooling. Monitor resource usage and uninstall apps that seem to cause overuse of your CPU, network, GPU or battery, especially while the phone screen is off. Problematic apps contribute heat.

Get a repair

For recurring overheating with no obvious cause, it may indicate a hardware defect like a faulty battery that needs replacement. Visit a repair shop to have your phone inspected in case internal damage or a defective part is causing the heating.

How can I prevent my phone from overheating?

Use these tips to minimize overheating occurrences:

Avoid heat sources

Keep your phone out of hot cars, away from heater vents, off hot surfaces, not under bed covers or pillows, and shaded from direct sun. Excess environmental heat is a huge contributor to phone overheating.

Use a heat dissipating case

Certain phone cases are designed with vents, cooling fans, heat spreaders, and heat conductive materials to direct heat away from your phone. They help mitigate heat from normal usage.

Limit gaming and video

Heavy gaming and video streaming are top causes of phone overheating. Avoid extended gaming sessions and use apps that limit frame rates. This reduces GPU and CPU load. Streaming less 4K or 8K video also helps.

Add phone cooling accessories

External phone cooling fans, heatsink cases, and clip-on cooling pads can augment your phone’s heat dissipation capabilities. They pull and spread heat away from your phone’s body.

Close unused apps

Don’t leave apps running indefinitely in the background. Swipe away apps you’re not actively using to free up system resources and reduce background processing that contributes heat. Unused open apps just waste CPU cycles.

Use airplane mode when possible

Periodically enabling airplane mode turns off power-hungry mobile data, WiFi, and cellular radio activity when you don’t need connectivity. These transmitters generate lots of heat.

Disable unneeded features

Turn off battery draining features like always-on display, raise to wake, auto-syncing, and vibrations. Reduce screen brightness and frame rates. Minimize phone features that passively consume power and add heat.

Avoid wireless charging

Wireless charging tends to heat phones more than wired charging. When possible, use cooler wired charging methods and avoid wireless charging pads if your phone is prone to getting hot. The wire allows heat dissipation.


Overheating is a common issue faced by smartphone users. While occasional mild overheating is normal, sustained high temperatures can degrade your phone’s performance and lifespan. Being mindful of environmental heat sources, limiting demanding usage, and allowing proper cool off periods helps mitigate overheating risks. With proper precautions, you can enjoy using your phone without the frustration of frequent shutdowns or throttling due to excess heat generation. Remember to stay cool!