All the devices that use motion sensors to try to count your steps aren't totally accurate. They need to try to detect the motion that your body makes when you take a step and count that, but they also need to ignore other movement, such as when you're driving along a bumpy road or shaking your leg when your phone is in your pocket. It's likely that when your holding your phone in your hand that you're also moving it around a bit and that extra motion is enough to make the phone think that you're not actually taking steps. Since it only counts flights of stairs if you take steps as you go up (or maybe down) and it doesn't think you're taking any steps then it won't count those flights either.
You could try to walk up some stairs with your phone in your hand and make an effort to hold your phone perfectly still relative to your body. My guess would be that it would count flights of stairs as accurately as it does with the phone in your pocket.
"Flights climbed" uses the barometer, not the accelerometer, which is used for step counting.
Flights climbed has been a hit/miss for my 6+ since day one.
I live 1.5 floors up from ground level and descend/climb these at least 3x day. Most days my iPhone reads 0 or 1. It is seldom correct.
Usually in my pack or pocket.
Same here. I gave up on the health app after quickly realising how woefully inaccurate it is.
Only works accurately when phone is in my pocket. If I'm holding it in my hand it doesn't register.
What's that all about?