Instinct Solar Abnormal Barometer Readings

Perhaps the good old clogging of the barometer port? Between SET and GPS buttons, where the side meets the backside. \

Thanks but i am not wearing the watch tightly. There shouldn't be any clogging.

It's not about wearing a watch tightly. It sleeps with dust, sweat, fiber from clothes. Try rinsing and drying the watch to see if it helped.

Tested for couple of days. Tried ringing and drying the watch more frequently but the issue still occurred several times. And I find this issue is very likely to happen after I climbed some floors. Thus I think it's a flaw of software.

My graph looks exactly like this after swimming in the pool. I know you are at home and probably not in a swimming pool, but perhaps during these 24 hours you were wearing it under water.

Thanks but I am 100% sure I have never put my watch underwater since I bought it. I know what you mean. I have a casio watch and indeed it would produce barometric graph like this when I put it underwater. But this garmin instinct solar has never been underwater.

Not even when bathing or showering? Rain, sweat. All you need is a sweaty hand under the clothes.

No bathing, no shower. Sweaty hand yes and often. But i am wearing T shirt all these days, so no sweaty hand under clothes.

The issue you have is caused by two things. 

First your sensor is set to Barometer instead of Auto mode, this means every time you altitude changes the barometer will have a random jump like the one you are seeing. It’s recommended the sensor is set to auto for the watch to chose based on your activity. 

The other plausible issue is water. IE: if you go for a swim and the watch is set to auto or Barometer mode only, the pressure in the water will mess with the barometer graph. It’s redonnes that, if you swim to set the sensor to altitude.