If you're wondering, yes, Monday is the coldest Feb. 23 in Toronto's history.

Environment Canada said the temperature sat at -21.2 C around 8 a.m., with a bone-chilling wind chill of -32 C. The temperature is set to climb to a high of -16 C today as the sun comes out.

Previously, the coldest Feb. 23 was in 1972, when it was -19. 4 C.

The plunge back into double-digit negative temperatures came as a shock after the mercury rose to –3.3 C on Sunday.

Many morning commuters had to endure more of the cold than normal after subway service was shut down between Union and Bloor stations. Outside, icicles hung from houses and buildings and sidewalks throughout the downtown were covered in a slippery mix of snow and ice.

Environment Canada issued an extreme cold warning while the city extended its citywide alert which opens extra shelter space and special warming stations.

Scarborough-Agincourt Coun. Norm Kelly pointed out the painful fact that 19 of the past 23 days have been cold enough for the city to declare extreme cold weather alerts.

Overall, the city has issued almost 30 cold weather alerts this winter, more than any other year except for the previous winter.

The average temperature for this month is –12.2 C with a high of –1.4 C.

The seasonal normal high for Feb. 23 is 1 C, Environment Canada records show.