Hamilton breaks weather record in December

If you thought this past December felt unusually warm in Hamilton, you would be correct.

According to Hamilton Weather Records, a social media account run by weather historian Rolf Campbell, the city stayed above -6.5 C for the first time since records started being kept.

“For the 1st time in recorded history, #Hamilton stayed above -6.5°C during an entire December (December 2023),” Campbell wrote on X. 

According to a graphic created by Campbell, the lowest temperature recorded in Hamilton in December 2023 was -6.1 C, the highest minimum temperature on record. The second warmest December in the chart occurred in 2015 when the minimum temperature sat at -6.6 C. 

Campbell’s chart suggests you’d have to go all the way back to 1881 to find a higher-than-normal minimum temperature, as the lowest temperature recorded that December was -6.7 C. 

The lowest recorded temperature for the city was -27.8 C in December 1871. 

According to Campbell, records started being kept in December 1866.

🥇For the 1st time in recorded history, #Hamilton stayed above -6.5°C during an entire December (December 2023). #YhmWx #YHM #ONWx pic.twitter.com/xMmhF8cRVN

— Hamilton Weather Records🌤 (@YHM_Weather) January 8, 2024

The unusually warm temperatures weren’t exclusive to Hamilton, but while some reports indicate Toronto had a record number of rainy days, the same wasn’t true for Steel Town or nearby Mississauga, according to Environment and Climate Change Canada.

Environment Canada keeps records at two locations in the Mississauga and Hamilton areas — Pearson Airport and John C. Munro Airport.

At Pearson Airport, there were 16 days with rain in December 2023, the sixth highest number of rainy days in December on record, Steven Flisfeder, an Environment and Climate Change Canada warning preparedness meteorologist, told insauga.com.

The highest number was 20 days in 1972.

At John C. Munro Airport in Hamilton, there were 13 days of rain reported in December–a tie with 2001 for the fifth most rainy days in December.

The record number of days reporting rain was 17 in 2015 for Hamilton.

With the rain, came a higher number of warmer days.

“It was warmer than normal,” Flisfeder said.

But there were no records set for daytime highs or daytime lows at Mississauga and Hamilton airports, he added. The daytime high and daytime low calculation is an average of all the maximum (for high) and minimum (for low) temperatures across the month.

John C. Munro had a third place for daytime high and a second place for daytime low. The warmest day was Dec. 9, when it reached 12.1 C.

Unfortunately, Environment Canada doesn’t keep records for the number of foggy days.

“Anecdotally, I can say it was definitely very foggy,” Flisfeder said.

– With files from Karen Longwell