The thermostat gets its time from the network and its location, and a wrong time on the display usually means the thermostat is offline or has the wrong location or time zone. Check the address and time zone for your home in the Google Home app and reconnect the thermostat to wifi, since it takes its time from the internet. A schedule that fires at the wrong hour follows the wrong clock. For a wrong status, the thermostat shows heating or cooling and the current temperature;
The checks in more detail
if the app disagrees with the display, refresh the app, check the thermostat is online and restart it. Google's article on strange heating or cooling issues covers a system that heats when it should cool, runs too long or turns on and off oddly, and has links to heat pump issues and to reversed heating and cooling. If the thermostat is stuck during startup, use Google's startup article. After a power cut it may take a few minutes to reconnect and may show a stale status meanwhile.
If the temperature reading looks wrong, check the thermostat is not in direct sun or near a vent, and compare with another thermometer. Daylight saving changes can shift the clock; a reconnection usually fixes it. Compare the display time with your phone at the same moment to see how far off it is. A reading that jumps when the sun hits the wall points at placement, not a fault. Contact support with a screenshot showing the offset.
Compare the thermostat's reading with a simple thermometer placed beside it for an hour, since a steady difference is calibration or placement and a wandering one points at drafts, sun or a nearby vent. Google's strange heating and cooling article covers a system that runs too long, turns on and off oddly or heats when it should cool, and its first step is to compare the settings and wiring with the equipment before assuming the thermostat's clock is at fault.
Differential
Likely causes of “Nest thermostats shows the wrong time, state or sensor reading”, and how to tell them apart
- 1
The wrong time zone
What separates it The schedule runs at the wrong hour because the home address gives the wrong time zone
How to confirm Correct the home address in the app, since the time zone follows the address
- 2
Offline
What separates it The time or status is stale because the thermostat is offline
How to confirm Reconnect the thermostat to wifi, so that it can sync the time again
- 3
Sun or a vent near it
What separates it The temperature reading is odd because the thermostat sits in the sun or near a vent
How to confirm Move it, or shade it, so that the reading reflects the true temperature of the room
- 4
A stuck startup
What separates it The thermostat never finishes booting because its startup is stuck
How to confirm See the startup article on Google's support site, and follow the steps it gives
- 5
A reversed system
What separates it Heating and cooling are swapped because the system type or the wiring is wrong
How to confirm Check the wiring and the system type in the settings, and correct any mistake
Before you touch a setting
Record this first — changing settings destroys the evidence
- The time shown on the thermostat compared with the real time
- The temperature that the thermostat reads compared with a thermometer
- The home address that is set in the Google Home app
Try in this order
0 of 7 completedCheck the home address
ReversibleCheck the home address and the time zone in the app, since they decide the time on the display.
Reconnect to wifi
ReversibleReconnect the thermostat to wifi, so that it can sync its clock with the network again.
Refresh the app
ReversibleRefresh the app and compare it with the display, to see which of the two shows the wrong value.
Check for sun or vents
ReversibleCheck for sun or vents near the thermostat, since they can push its temperature reading up or down.
Restart the thermostat
ReversibleRestart the thermostat if it is stuck, which keeps all of your settings and often fixes it.
Read the strange heating article
ReversibleRead the strange heating article for odd behavior, since it explains wiring and system type mistakes.
Contact Google
ReversibleContact Google if it stays wrong, and give them the time shown and the real time.
Model-specific
What is true of this model and not of its siblings
- Clock
- Follows the network and location.
- Readings
- Can be skewed by sun or vents.
Stop boundary
When this stops being a self-service repair
- !If the time stays wrong after reconnecting, contact Google Nest support
- !If heating and cooling are reversed, check the wiring
- !If it runs constantly, contact an HVAC pro
Evidence ledger
Sources behind this answer
Heating and cooling faults.
Startup problems.
Offline steps by model.
Restart versus reset.
The company and its products.
Exact questions
Common questions
Why does my schedule fire late?+
A schedule fires late when the clock is wrong, so check the address and the time zone.
Can sun affect the reading?+
Yes, sun on the thermostat can push its temperature reading up, so shade it.
What if heating and cooling are swapped?+
If heating and cooling are swapped, check the wiring and the system type in the settings.
Should I restart?+
Restart it if it is stuck, since a restart keeps your settings and fixes many problems.