It happened 100 years ago. For a seven-day stretch ending on Jan. 4, 1918, the mercury in Boston never climbed above 20 degrees.

Only once before has the city endured seven straight days of such frigid temperatures.

Forecasters are predicting that for the next week — from Wednesday through Tuesday, Jan. 2 — temperatures in Boston won’t crack 20 degrees.

However, that century-old cold snap included more extreme low temperatures than what meteorologists are expecting we’ll see in the coming days.

For a record five days in a row — from Dec. 29, 1917, through Jan. 2, 1918 — low temperatures in the city were recorded below zero, including readings of -11 and -14.


Over the coming week, forecasts call for temperatures to only dip as low as zero in Boston (though in the interior of the state it will plunge below zero).

The second longest streak of sub-20 weather was six days in late January 1888.

And in the Februaries of 1979 and 1899, and in late December 1872, the city shivered through five straight days of below-20 temperatures.

Matt Rocheleau can be reached at matthew.rocheleau@globe.com. Follow him on Twitter @mrochele.