# Metview Macro

#  **************************** LICENSE START ***********************************
# 
#  Copyright 2015 ECMWF. This software is distributed under the terms
#  of the Apache License version 2.0. In applying this license, ECMWF does not
#  waive the privileges and immunities granted to it by virtue of its status as
#  an Intergovernmental Organization or submit itself to any jurisdiction.
# 
#  ***************************** LICENSE END ************************************

jan    = read("era_t2m_jan_2009_2013.grib")
jan_00 = read(data: jan, time: 00) # filter the 00:00 fields
jan_12 = read(data: jan, time: 12) # filter the 12:00 fields

jan_00_mean = mean(jan_00)
jan_12_mean = mean(jan_12)

jan_means = jan_00_mean & jan_12_mean

return jan_means
