Sion has a population of. Most of the population speaks French as their first language, German is the second most common and Portuguese is the third. There are 915 people who speak Italian and 20 people who speak Romansh. , the gender distribution of the population was 48.3% male and 51.7% female. The population was made up of 15,250 Swiss men and 4,787 non-Swiss men. There were 16,910 Swiss women and 4,537 non-Swiss women. Of the population in the district 14,700 or about 39.7% were born in Sion and lived there in 2000. There were 9,873 or 26.7% who were born in the same canton, while 3,986 or 10.8% were born somewhere else in Switzerland, and 7,258 or 19.6% were born outside of Switzerland. , there were 15,728 people who were single and never married in the district. There were 17,375 married individuals, 2,099 widows or widowers and 1,791 individuals who are divorced. There were 4,974 households that consist of only one person and 967 households with five or more people. Out of a total of 15,344 households that answered this question, 32.4% were households made up of just one person and there were 146 adults who lived with their parents. Of the rest of the households, there are 3,694 married couples without children, 4,762 married couples with children There were 1,065 single parents with a child or children. There were 245 households that were made up of unrelated people and 458 households that were made up of some sort of institution or another collective housing. The historical population is given in the following chart: Colors= id:lightgrey value:gray id:darkgrey value:gray ImageSize = width:960 height:210 PlotArea = height:150 left:100 bottom:50 right:100 AlignBars = justify DateFormat = x.y Period = from:0 till:37000 TimeAxis = orientation:vertical AlignBars = justify ScaleMajor = gridcolor:darkgrey increment:7000 start:0 ScaleMinor = gridcolor:lightgrey increment:1400 start:0 PlotData= color:yellowgreen width:40 mark: align:center bar:1850 from:start till:6287 text:"6,287" bar:1860 from:start till:7964 text:"7,964" bar:1870 from:start till:9103 text:"9,103" bar:1880 from:start till:9318 text:"9,318" bar:1888 from:start till:9911 text:"9,911" bar:1900 from:start till:10871 text:"10,871" bar:1910 from:start till:11765 text:"11,765" bar:1920 from:start till:12207 text:"12,207" bar:1930 from:start till:13429 text:"13,429" bar:1941 from:start till:15430 text:"15,430" bar:1950 from:start till:17327 text:"17,327" bar:1960 from:start till:22581 text:"22,581" bar:1970 from:start till:28305 text:"28,305" bar:1980 from:start till:30273 text:"30,273" bar:1990 from:start till:33976 text:"33,976" bar:2000 from:start till:36993 text:"36,993"
Mergers and name changes
On 17 November 1962, Bramois merged into the municipality of Sion.
On 1 January 2013 the former municipality of Salins merged into the municipality of Sion.
On 1 January 2017 the former municipality of Les Agettes merged into the municipality of Sion.
Politics
In the 2007 federal election, the most popular party was the CVP which received 37.31% of the vote. The next three most popular parties were the SP, the SVP and the FDP. In the federal election, a total of 15,459 votes were cast, and the voter turnout was 59.9%. In the 2009 Conseil d'Etat/Staatsrat election, a total of 13,603 votes were cast, of which 1,334 or about 9.8% were invalid. The voter participation was 52.7%, which is similar to the cantonal average of 54.67%. In the 2007 Swiss Council of States election a total of 15,234 votes were cast, of which 1,196 or about 7.9% were invalid. The voter participation was 60.0%, which is similar to the cantonal average of 59.88%.
Religion
From the, 29,644 or 80.1% were Roman Catholic, while 1,708 or 4.6% belonged to the Swiss Reformed Church. Of the rest of the population, there were 241 members of an Orthodox church, there were 22 individuals who belonged to the Christian Catholic Church, and there were 629 individuals who belonged to another Christian church. There were 16 individuals who were Jewish, and 1,429 who were Islamic. There were 93 individuals who were Buddhist, 52 individuals who were Hindu and 25 individuals who belonged to another church. 1,704 belonged to no church, are agnostic or atheist, and 1,735 individuals did not answer the question.
Weather
Sion town has an average of 82.6 days of rain or snow per year and on average receives of precipitation. The wettest month is December during which time Sion receives an average of of rain or snow. During this month there is precipitation for an average of 7.4 days. The month with the most days of precipitation is August, with an average of 8.2, but with only of rain or snow. The driest month of the year is April with an average of of precipitation over 5.9 days.
Education
In Sion about 11,917 or of the population have completed non-mandatory upper secondary education, and 4,922 or have completed additional higher education. Of the 4,922 who completed tertiary schooling, 56.8% were Swiss men, 30.7% were Swiss women, 7.0% were non-Swiss men and 5.6% were non-Swiss women.
