Hot on the heels of Wednesday’s 99-degree record high at Reagan National Airport, Washington’s official observation station, the mercury spiked to 102 degrees Thursday, equaling the record for the date set in 1874. The 102-degree reading also matched the warmest temperature reached in the month of June since records started being kept in 1871.

The blistering temperature represents the second-earliest reading of at least 100 degrees on record. The earliest occurred June 5, 1925.

The last occurrence of 100 in June in Washington was June 24, which was the beginning of the region’s blistering 2010 summer. With Thursday’s 102, the temperature rose to at least the century mark in the month of June in back-to-back years for the first time since 1933 and 1934, the only other such instance.

Record highs were also set at Baltimore-Washington International Marshall and Dulles International airports Thursday, which hit 100 and 97, respectively. At BWI, which climbed to 99 Wednesday, it was also the second straight record-hot day. Philadelphia (99 degrees) and Atlantic City (102) were among many other cities in the mid-Atlantic to set record highs Thursday.

Fewer than 10 days into June, Washington has already reached at least 95 degrees five times. The annual average is between seven and eight such days.

Days at or above 90 degrees are mounting at a similarly torrid pace to last year’s, when the region reached the milestone 67 times, tying 1980 for the most on record. The mercury has reached at least 90 on seven occasions in 2011. At this time last year, there had been eight days at or above 90.

The recent heatwave arose from a massive area of high pressure that developed in the Southwest and South and expanded northeastward over the past five days.

In Houston, record highs were set on five of the first six days of June, including a scorching 105 on Sunday. On Tuesday, Minneapolis surged to 103, its hottest day since July 31, 1988, and its second-hottest June temperature on record. Between June 1 and 8, more than 1,400 record-high temperatures were set across the United States, compared with about 120 record lows.

A cold front that sliced through the northern Plains and the Midwest on Wednesday has put an end to the scorching heat there and is expected to lower temperatures in the Northeast and eventually the mid-Atlantic between Friday and the end of the weekend.

Thunderstorms are likely to accompany the front around Washington, especially later into the day on Friday and Saturday.

Capital Weather Gang’s Ian Livingston contributed to this report.