Map showing record highs (red) and lows (blue) on June 21, 2012 - the first full “official” day of summer. View Climate Central interactive record temperature tool. (Climate Central)

Wednesday and Thursday, more than 500 record high temperatures were tied or set in the U.S. (some of these in the Midwest and Southwest) compared to just 74 record low temperatures (mainly in the Northwest).

The core of the heat aligned with I-95 cities from the mid-Atlantic northward.

Richmond, Newark, and New York City were among a set of cities and towns that set records highs in the mid-to-upper 90s on Wednesday.

On Thursday, Washington, D.C. established a new record high, soaring to 99. Baltimore did one better, reaching the century mark - tying the record set in 1923. Record highs in the upper 90s were also set in New York City, Hartford and Boston.

Davion Brown, 28, acclimates Zavionn Boomer, 2, to the water while Kaia Brown 7, and Tyler Brown, 9, dip their hands into the stream from the tapped fire hydrant on the 1700 block of W St. in Washington, DC's Anacostia neighborhood on June 21, 2012. Much of the Anacostia area was stricken by power outages today, forcing many outside -- into the record heat -- looking for a way to cool down. (Daniel C. Britt/THE WASHINGTON POST)

AccuWeather has put together some nice tables showing record highs day-by-day this week.

A considerable portion of the high temperature records set were for low temperatures, as the nighttime hours provided little relief from the oppressive heat. Climate Central’s Andrew Freedman describes the remarkable high minimum temperature record set in Boston Thursday:

In Boston, the low temperature on June 21 only fell to 80°F, which set a record for the date and marks only the second time that an 80-degree low temperature was recorded during June. The last time such a warm overnight temperature was recorded was on June 6, 1925, according to the National Weather Service.

Washington, D.C. also set a record high minimum temperature Thursday, dipping to just 78 as did New York City (both airports), only bottoming out at 79.