JACKSONVILLE, Fla. – Summer began on June 21 and 2 days later it reached the hottest day of the year so far at 100 in Jacksonville. The record set broke the previous high of 99°.
This Thursday, extreme 100-degree heat is expected in Jacksonville -- which is something the city has not seen since May 27, 2019.
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While the heat index has frequently topped 100 degrees, readings of actual air temperatures over 99° have only occurred five times over the last 22 years. The most recent hottest temperature at Jacksonville International Airport was the record of 100° set June 23, 2022, followed by 2019 and 101 in 2016. In 2010, a record of 102° was set and 103° occurred in the summer of 2000.
Meteorological summer is the hottest time of the year from June through August and looking at weather records for Jacksonville shows July is the most brutal when it comes to heat.
For example, the hottest day ever recorded in the city was 105° set in July 1942 before records were moved out to Jacksonville International Airport.
But sometimes the heat hits earlier as it did on May 21, 1938. That date marked the earliest reading in the year over 100 degrees. There were only two other times with triple digits in May including the most recent on the 27th of 2019.
The hottest summers in Jacksonville based on average high temperatures occurred in:
- 1954 at 94.2F
- 1981 at 93.5F
- 2016 tied with 2010 in third place at 93.4F.
So while Tuesday marks the start of astronomical summer and the longest day of the year, the heat usually breaks when average highs dip into the upper 80s in September, well before the end of the official summer season.
Story updated to add 100° high on May 27, 2019.