Weinfelden has a population () of . , 19.9% of the population are foreign nationals. Over the last 10 years (1997–2007) the population has changed at a rate of 6.5%. Most of the population () speaks
German (86.7%), with
Italian being second most common ( 3.2%) and
Albanian being third ( 2.4%). , the gender distribution of the population was 49.9% male and 50.1% female. The population was made up of 3,903 Swiss men (39.0% of the population), and 1,086 (10.9%) non-Swiss men. There were 4,116 Swiss women (41.1%), and 901 (9.0%) non-Swiss women. , there were 4,116 private households in the municipality, and an average of 2.2 persons per household. There were 2,423 (or 25.6%) persons who were part of a couple without children, and 4,489 (or 47.5%) who were part of a couple with children. There were 465 (or 4.9%) people who lived in single parent home, while there are 44 persons who were adult children living with one or both parents, 29 persons who lived in a household made up of relatives, 100 who lived in a household made up of unrelated persons, and 362 who are either institutionalized or live in another type of collective housing. The vacancy rate for the municipality, , was 1.51%. , the construction rate of new housing units was 2.6 new units per 1000 residents. the average price to rent an average apartment in Weinfelden was 938.69
Swiss francs (CHF) per month (US$750, £420, €600 approx. exchange rate from 2000). The average rate for a one-room apartment was 485.07 CHF (US$390, £220, €310), a two-room apartment was about 715.31 CHF (US$570, £320, €460), a three-room apartment was about 838.46 CHF (US$670, £380, €540) and a six or more room apartment cost an average of 1456.25 CHF (US$1160, £660, €930). The average apartment price in Weinfelden was 84.1% of the national average of 1116 CHF. In the
2007 federal election the most popular party was the
SVP which received 34.16% of the vote. The next three most popular parties were the
FDP (18.78%), the
CVP (16.11%) and the
SP (10.75%). In the federal election, a total of 3,415 votes were cast, and the
voter turnout was 51.0%. The historical population is given in the following table: ==Heritage sites of national significance==