Tech workers come in droves to Silicon Valley, but few can afford to buy homes there.

Recent data shows that prospective homebuyers are migrating south in search of affordability.

The real-estate company Redfin produces an annual list of the hottest housing markets in America, based on increases in internet traffic to listings in a neighborhood. In 2018, nine of the 10 hottest 'hoods are in the San Jose metro area, in the heart of Silicon Valley.

According to Redfin, San Jose's ultracompetitive housing market had the lowest housing supply and the fastest pace of home sales compared with any other Redfin market in December. The median sale price climbed 32% year over year, reaching $1.1 million that month.

San Jose most likely won't be "affordable" for long.

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