CoolGuard

CoolGuard keeps an eye on your phone's heat — and at night, it's the clock on your nightstand.

A hot iPhone runs slower, its battery ages faster, and in summer it heats up within moments in the sun or while gaming, navigating, or charging. CoolGuard shows you where your phone stands on a four-level scale (Normal, Slightly Warm, Hot, Critical), warns you in time, and tells you what to do.

HEAT MONITORING
• Live heat level on the main screen, with a color-coded ring and a quick tip
• Heat Trend: 1-hour and 24-hour curves in a banded or clean style — drag your finger to read the details
• Heat Log with calendar and map: when and where your phone got hot
• Alerts from the level you choose: push notifications, sound alerts, quiet hours
• Monitor Mode: background monitoring, with a Live Activity on the Lock Screen and in the Dynamic Island
• Cooling tips and a carefully curated selection of active coolers

NIGHT CLOCK AND ALARM
• Sleep Mode: dark screen with just the clock and the outdoor temperature — three sizes, your choice of color
• Alarms: up to 10, repeating daily; on iOS 26 and later they ring through the system alarm, even when your phone is silenced
• Landscape view: big clock, swipeable alarm bar, brightness slider
• Burn-in protection: slow pixel drift and dimming to keep your display safe
• 12- or 24-hour clock, with seconds if you like

WEATHER
• Outdoor temperature, with today's and tomorrow's highs and lows
• Weather face in the ring: the sun and moon travel around it from sunrise to sunset
• A warning on dangerously hot days

WIDGET
• Small: thermometer, weather, battery level, clock
• Medium: adds the heat trend curve and the date
• Works on the Lock Screen, too

BATTERY
• Battery Health and cycle count, compared month by month with your phone's heat

MORE
• 50 languages, Celsius or Fahrenheit
• Private by design: no ads, no analytics, no accounts — your Heat Log never leaves your phone
• Free — you can support development with a tip

Note: iOS doesn't expose exact temperatures to apps — CoolGuard shows Apple's four official thermal levels.