An aerodrome meteorologist measures the QNH as 1008.8 hPa. What QNH value will be reported on the METAR or in the ATIS?
Learning Objective 010.07.02.09.04: State in which margin altimeter settings provided to aircraft shall be rounded up or down. Source: ICAO Doc 4444, Chapter 4, 4.10.4 Provision of altimeter setting information
ICAO Doc. 4444 (PANS-ATM)
4.10 - ALTIMETER SETTING PROCEDURES
4.10.4 - Provision of altimeter setting information
4.10.4.7 - Altimeter settings provided to aircraft shall be rounded down to the nearest lower whole hectopascal.
There is good reason for rounding down the altimeter settings, if they are not exactly on a whole hectopascal. Rounding a QNH down would mean that the aircraft would indicate slightly lower than it's actual altitude, so the pilot would fly slightly higher than they need to, which is the safe side, and better than flying slightly low.
ICAO Doc. 4444 (PANS-ATM)
4.10 - ALTIMETER SETTING PROCEDURES
4.10.4 - Provision of altimeter setting information
4.10.4.7 - Altimeter settings provided to aircraft shall be rounded down to the nearest lower whole hectopascal.
There is good reason for rounding down the altimeter settings, if they are not exactly on a whole hectopascal. Rounding a QNH down would mean that the aircraft would indicate slightly lower than it's actual altitude, so the pilot would fly slightly higher than they need to, which is the safe side, and better than flying slightly low.
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