When warm becomes the norm: April nearly sets a new bar for heat

 It may already feel like a distant memory with this early-May chill in the air, but April brought some serious heat to the Tri-State. Temperatures reached into the 90s on 2 days of the month, April 13th and 14th. Overall, we finished with an average temperature of 57.6°, making April 2023 the 2nd-warmest on record in NYC. The chart below from New York's local National Weather Service office will need some updating:

Top 10 warmest and coldest Aprils on record.
Data and chart from NWS Upton, NY

With last month added to the list of warmest Aprils, the list will be further stacked with records from this century. By contrast, May has gotten off to a cool start. Both Monday and Tuesday's high temperatures were well below the average high of 68°, and the average temperature for the month is 7° below average so far. However, it's quite unlikely that this month will make it onto the top 10 coldest list below:

Top 10 warmest and coldest Mays on record.
Data and chart from NWS Upton, NY

The rationale is simple, even without knowledge of the upcoming forecast. It's unlikely that this month will be one of the coldest Mays on record because it's been 56 years since May temperatures have been chilly enough to make the list!

 

The near-record warmth in April is just a small part of an ongoing trend, which is easier to see when looking at Central Park's complete records dating all the way back to 1869. 154 years is long enough to have seen lots of ups and downs. But what we've seen instead is an increase in warm temperature records, while cold temperature records have almost disappeared. The chart below shows the number of months on the top 10 record warm versus cold lists through the decades (tied records are included). Again, all data is from NWS New York. 

The trend of record-breaking months may be a better indication of our warming world than the often-cited daily temperature records. While a daily record high can be caused by a brief spike in temperatures or by an unusual weather pattern, the monthly average temperature takes it all into account- highs and lows- through the course of an entire month. 

Despite this early May cooldown, 2023 has been a warm year so far. January set a new record in Central Park; the average temperature of 43.5° was nearly 10 degrees above normal. And February was not far behind. With an average temp of 41.1°, February 2023 will take the #3 spot on the all-time list. A looming El Niño increases the chance for a hot summer in the Tri-State. More on that coming later this week. Stay tuned!