The Factual API exposes hours of operation as well. This is in the Restaurant API, which consists of 800k restaurants in the US. The field is structured as a JSON hash where each day of the week is indexed by an integer cf. ISO-8601: 1 = Monday through 7 = Sunday.
Docs - http://developer.factual.com/display/docs/Places+API+-+Restaurants
Demo of restaurant data - http://www.factual.com/data/t/restaurants-us
Example of a restaurant entity.
24: 24,
open_24hrs: false,
accessible_wheelchair: true,
address: "3274 21st St",
alcohol: false,
alcohol_bar: false,
alcohol_beer_wine: false,
alcohol_byob: false,
attire: "casual",
category: "Food & Beverage > Restaurants > Pizza",
country: "US",
cuisine: "Pizza, Italian, American, Fast Food, Pasta",
factual_id: "5873129b-11e9-49db-a012-967b4046420d",
fax: "(415) 695-1687",
founded: "1999",
groups_goodfor: false,
hours: "{"1":[["11:00","24:00"]],"2":[["11:00","24:00"]],"3":[["11:00","24:00"]],"4":[["11:00","24:00"]],"5":[["11:00","1:00"]],"6":[["11:00","1:00"]],"7":[["11:00","24:00"]]}",
kids_goodfor: true,
latitude: 37.75694,
locality: "San Francisco",
longitude: -122.42052,
meal_cater: true,
meal_deliver: true,
meal_dinner: true,
meal_lunch: true,
meal_takeout: true,
name: "Serrano's Pizza and Pasta",
options_vegan: true,
options_vegetarian: true,
owner: "Serranos Pizza",
parking: true,
payment_cashonly: false,
postcode: "94110",
price: 2,
rating: 4.5,
region: "CA",
reservations: false,
seating_outdoor: true,
smoking: false,
status: "1",
tel: "(415) 695-1615",
website: "http://www.serranospizza.com/"