Thank you.
Can you please add hpa calculation also to BME280 ?
How can I add pow function manually in constructor ?
About Mean pressure here is quote:
To compare pressure conditions around the world, meteorologists recalculate the barometric pressure measured at weather stations to mean sea-level conditions.
Higher placed weather stations naturally have lower atmospheric pressure since the column of air above them is less high. At higher altitude the air pressure decreases. Since air pressure decrease due height above sea level is equivalent around the world, barometric pressure readings from weather stations located at any altitude can be equivalently converted into mean sea level pressure. Mean sea level pressure is the pressure your weather reporting station would have, if it was moved down to sea-level. Mean sea level pressure is generally higher than your measured pressure, which is called barometric pressure.
This will be usefull function if somebody wants to use esp as weather station.
Here is the link for more information and formula:
http://barani.biz/apps/sea-level-pressure/