Heat Index Counts for the Jacksonville International Airport (JAX), 1948 – 2024
Values represent the total number of days when the maximum heat index reached or exceeded each threshold temperature. Individual years in the period of record without data are excluded.
| Year | ≥100ºF | ≥105ºF | ≥108ºF | ≥110ºF | ≥115ºF |
| 1948 | 34 | 6 | 1 | 0 | 0 |
| 1949 | 56 | 9 | 4 | 1 | 0 |
| 1950 | 27 | 8 | 3 | 1 | 0 |
| 1951 | 43 | 10 | 1 | 0 | 0 |
| 1952 | 47 | 14 | 6 | 3 | 0 |
| 1953 | 25 | 6 | 1 | 0 | 0 |
| 1954 | 44 | 15 | 3 | 1 | 0 |
| 1955 | 29 | 0 | 0 | 0 | 0 |
| 1956 | 31 | 3 | 1 | 0 | 0 |
| 1957 | 41 | 13 | 4 | 1 | 0 |
| 1958 | 23 | 2 | 0 | 0 | 0 |
| 1959 | 22 | 5 | 0 | 0 | 0 |
| 1960 | 33 | 3 | 0 | 0 | 0 |
| 1961 | 27 | 2 | 0 | 0 | 0 |
| 1962 | 41 | 7 | 2 | 1 | 0 |
| 1963 | 28 | 1 | 0 | 0 | 0 |
| 1964 | 23 | 2 | 0 | 0 | 0 |
| 1965 | 21 | 1 | 0 | 0 | 0 |
| 1966 | 8 | 1 | 0 | 0 | 0 |
| 1967 | 8 | 0 | 0 | 0 | 0 |
| 1968 | 31 | 4 | 0 | 0 | 0 |
| 1969 | 35 | 6 | 2 | 1 | 0 |
| 1970 | 34 | 6 | 2 | 1 | 1 |
| 1971 | 15 | 1 | 0 | 0 | 0 |
| 1972 | 24 | 2 | 2 | 0 | 0 |
| 1973 | 25 | 2 | 0 | 0 | 0 |
| 1974 | 6 | 0 | 0 | 0 | 0 |
| 1975 | 26 | 0 | 0 | 0 | 0 |
| 1976 | 30 | 5 | 0 | 0 | 0 |
| 1977 | 62 | 8 | 2 | 1 | 0 |
| 1978 | 45 | 11 | 5 | 3 | 0 |
| 1979 | 44 | 11 | 3 | 0 | 0 |
| 1980 | 83 | 28 | 16 | 12 | 5 |
| 1981 | 69 | 41 | 19 | 12 | 2 |
| 1982 | 58 | 15 | 6 | 1 | 0 |
| 1983 | 45 | 11 | 5 | 3 | 0 |
| 1984 | 18 | 1 | 1 | 1 | 0 |
| 1985 | 30 | 5 | 4 | 2 | 1 |
| 1986 | 49 | 8 | 5 | 3 | 0 |
| 1987 | 57 | 15 | 4 | 3 | 0 |
| 1988 | 38 | 9 | 0 | 0 | 0 |
| 1989 | 40 | 5 | 2 | 0 | 0 |
| 1990 | 46 | 11 | 2 | 0 | 0 |
| 1991 | 66 | 8 | 3 | 1 | 0 |
| 1992 | 43 | 6 | 1 | 0 | 0 |
| 1993 | 65 | 20 | 11 | 5 | 0 |
| 1994 | 34 | 3 | 0 | 0 | 0 |
| 1995 | 44 | 15 | 7 | 2 | 0 |
| 1996 | 23 | 4 | 2 | 1 | 0 |
| 1997 | 33 | 3 | 2 | 2 | 0 |
| 1998 | 70 | 26 | 13 | 3 | 1 |
| 1999 | 35 | 15 | 8 | 5 | 2 |
| 2000 | 34 | 5 | 3 | 1 | 0 |
| 2001 | 19 | 1 | 0 | 0 | 0 |
| 2002 | 20 | 4 | 1 | 0 | 0 |
| 2003 | 12 | 0 | 0 | 0 | 0 |
| 2004 | 36 | 6 | 1 | 0 | 0 |
| 2005 | 51 | 11 | 2 | 1 | 0 |
| 2006 | 23 | 2 | 0 | 0 | 0 |
| 2007 | 36 | 10 | 4 | 1 | 0 |
| 2008 | 13 | 1 | 0 | 0 | 0 |
| 2009 | 36 | 7 | 2 | 0 | 0 |
| 2010 | 72 | 28 | 4 | 3 | 1 |
| 2011 | 46 | 7 | 2 | 1 | 0 |
| 2012 | 29 | 5 | 2 | 0 | 0 |
| 2013 | 26 | 0 | 0 | 0 | 0 |
| 2014 | 24 | 4 | 0 | 0 | 0 |
| 2015 | 46 | 10 | 3 | 0 | 0 |
| 2016 | 59 | 11 | 3 | 0 | 0 |
| 2017 | 51 | 8 | 2 | 1 | 1 |
| 2018 | 56 | 4 | 0 | 0 | 0 |
| 2019 | 48 | 11 | 5 | 2 | 0 |
| 2020 | 55 | 10 | 2 | 0 | 0 |
| 2021 | 25 | 4 | 1 | 0 | 0 |
| 2022 | 53 | 13 | 2 | 0 | 0 |
| 2023 | 60 | 22 | 12 | 6 | 1 |
| 2024 | 62 | 26 | 3 | 0 | 0 |
| Average | 38 | 8 | 3 | 1 | 0 |
