By Amanda Delgado – Updated Mar 24, 2022

A quick glance at an Acu‑Rite wireless thermometer lets you gauge indoor and outdoor temperatures—and even check the local time—before you step outside. This guide walks you through installing the sensor, powering the display, and customizing your settings with confidence.

Step 1: Install the Sensor Batteries

1. Open the battery cover on the outdoor sensor.
2. Insert two fresh AA batteries.
• Left side: positive end up.
• Right side: negative end up.
3. Replace the cover.

Step 2: Power the Main Unit

1. Open the battery compartment on the display unit.
2. Insert two AAA batteries.
• Top battery: positive end to the right.
• Bottom battery: negative end to the right.
3. Close the cover.

Step 3: Allow Synchronization

Give the sensor and display a few minutes to sync. On the main unit, look for the wireless signal icon next to the outdoor temperature. It should show one to four bars when communication is stable.

Step 4: Set the Clock

Press and hold the Set button (bottom of the unit) for 5 seconds to enter Clock Set Mode. A blinking cursor indicates the current setting:
• Clock Hour Mode (12‑hour or 24‑hour)
• Clock Hour
• Clock Minute.
Use the Plus symbol next to Set to cycle through options (press quickly for fast navigation). Press Set to confirm and move to the next item. Any time, hold Set to return to the main screen. If you idle for 30 seconds, the unit exits Clock Set Mode automatically.

Step 5: Choose Temperature Units

Press the F/C button above Set to toggle between Fahrenheit and Celsius display.

Things You’ll Need

• Acu‑Rite wireless thermometer kit
• 2 AA batteries (use lithium for cold climates)
• 2 AAA batteries (avoid rechargeable types)

TL;DR (Too Long; Didn’t Read)

• Use lithium batteries outdoors in sub‑4°F conditions; alkaline batteries can fail after prolonged exposure.
• Do not use rechargeable batteries—they operate at higher voltages.
• Resynchronization after battery replacement may take up to 20 minutes.
• Clock Set Mode auto‑exits after 30 seconds of inactivity.
• Clear stored max temperatures: press MIN/MAX once, then hold until dashes appear. Clear min temperatures: press MIN/MAX twice, then hold until dashes appear.