Composition of Earth's atmosphere by volume. The lower pie represents the trace gases that together compose about 0.038% of the atmosphere (0.043% with CO 2 at 2014 concentration). The numbers are from a variety of years (mainly 1987, with CO 2 and methane from 2009) and do not represent any single source.ifty percent of the total mass of the atmosphere is located in the lower 5.6 km (18,000 ft) of the troposphere. It is primarily composed of nitrogen (78%) and oxygen (21%) with only small concentrations of other trace gases.
Long range weather outlook for Montreal includes 14 day forecast summary: The forecast for Montreal in the coming two weeks is predicting the average daytime maximum temperature will be around 12Â°C, with a high for the two weeks of 18Â°C expected on the afternoon of Monday 24th. The average minimum temperature will be 5Â°C, dipping to its lowest on the morning of Tuesday 18th at -1Â°C.
Share: Facebook Tweet Google+. The best times to visit Montreal are from March to May and from September to November, when the weather is milder and hotel vacancies run amok. But aside from fluctuating rates, you'll discover that there really isn't a bad time to vacation here.