Question: When does it start to snow in the largest metropolitan area as measured by population of the country holding the exhibit of the Commission on modernization and technological development?

<P0-S0> the phoenix metropolitan area -- often referred to as the valley of the sun, the salt river valley or metro phoenix -- is a metropolitan area, centered on the city of phoenix, that includes much of the central part of the u.s. state of arizona. <P0-S1> the united states census bureau designates the area as the phoenix - mesa - scottsdale metropolitan statistical area (msa), defining it as maricopa and pinal counties. <P0-S2> as of the census bureau's 2015 population estimates, metro phoenix had 4,574,351 residents, making it the 12th largest metropolitan area in the nation by population. <P0-S3> the gross domestic product of the phoenix metropolitan area was $215 billion in 2014, 15th largest amongst metro areas in the united states. <SEP> <P1-S0> Saint Petersburg (Russian: Санкт - Петербу́рг, tr. <P1-S1> Sankt - Peterburg, IPA: (ˈsankt pjɪtjɪrˈburk) (listen)) is Russia's second - largest city after Moscow, with 5 million inhabitants in 2012, part of the Saint Petersburg agglomeration with a population of 6.2 million (2015). <P1-S2> An important Russian port on the Baltic Sea, it has a status of a federal subject (a federal city). <SEP> <P2-S0> oklahoma city is the capital and largest city of the state of oklahoma. <P2-S1> the county seat of oklahoma county, the city ranks 27th among united states cities in population. <P2-S2> the population grew following the 2010 census, with the population estimated to have increased to 620,602 as of july 2014. as of 2014, the oklahoma city metropolitan area had a population of 1,322,429, and the oklahoma city-shawnee combined statistical area had a population of 1,459,758 (chamber of commerce) residents, making it oklahoma's largest metropolitan area. <P2-S3> oklahoma city's city limits extend into canadian, cleveland, and pottawatomie counties, though much of those areas outside of the core oklahoma county area are suburban or rural (watershed). <P2-S4> the city ranks as the eighth-largest city in the united states by land area (including consolidated city-counties; it is the largest city in the united states by land area whose government is not consolidated with that of a county or borough). <SEP> <P3-S0> Snow cover (averaging 3 -- 5 months per year) is formed at the beginning of November and melts in beginning of April, but in recent years snow cover has lasted shorter than usual. <P3-S1> For example, in the winter of 2006 -- 2007 the snow cover did n't form until the end of January, and melted at the beginning of March; in 2007 -- 2008, the snow cover melted at the end of February, and in the 2008 -- 2009 winter, snow cover did n't form until the end of December, which is one month later than usual. <P3-S2> Yet in 2011 - 2012 it melted in the middle of April. <SEP> <P4-S0> June 17–19, 2010During Petersburg Economic Forum, President of the Russian Federation D.A. <P4-S1> Medvedev visited the exhibit of the Commission on modernization and technological development of the economy of Russia, where he watched the demonstration of Corporation’s developments in the field of 3D TV, namely, the first Russian 3D channel – 3DV.