September 2024 was the hottest on record in Denver

Denver continues to add late season 90-degree days, contributing to the warmest September on record. This comes on the heels of the 2nd warmest summer (2024) in history for Denver.

September had an average temperature, the average of daily high and low, of 70.3 degrees. This breaks the old record of 69.4 degrees set back in 2015. The third warmest was 2019 at 69.3 degrees, fourth was in 2022 at 69 degrees and fifth was 68.8 degrees in 2021. This puts September almost a full degree above the next warmest month in the history books.

September typically averages 2 days at or above 90 degrees. Things were a little different this year with 8 days of 90+ degrees.

This brings our year-to-date count of 90+ degrees days to 64 days. This is also an unusually high number. For example, we only average about 46 of these days a year, and only had 39 in 2023.

Assuming Denver will not break 90 degrees again this year, we will finish tied for 3rd behind only 2012 (73 days) and 2020 (75 days).