The update was first noticed by Sergey Alakov, a Canadian SEO expert, who monitored how Google was testing price trends for local hotel listings for more than five months. As you notice in the embedded tweet, the widget also shows amenities and allows users to refine searches based on weekly or monthly trends.
Google has begun rolling hotel pricing trends graph on mobile, according to Barry Schwartz over at Search Engine Roundtable. The update is significant for hoteliers as it means that potential guests can now see price fluctuations over a certain period of time, which may lead to a shift in booking patterns. The new feature shows the best prices for a one-night stay, drawing prices from Expedia, Booking, Orbitz, and others. The pricing trends graph appears below the sponsored hotel rates.