National Weather ServiceDelawareHeat AdvisoryArchive to October 1, 2026
Heat Advisories in Delaware
The National Weather Service issued 9 heat advisories for Delaware in 2025 and 6 a year on average in 2008-2025; in 2021-2025 it had the 44th most of any state. 2026 through September: 9, 57% above the average of 6 for those months in 2008-2025. New Castle was covered most often (75 times since 2008).
How many heat advisories does Delaware get?
Every heat advisory that covered part of Delaware. 2026 is an outline: the year is not over.
The numbers
| Year | Count |
|---|---|
| 2026 (through September) | 9 |
| 2025 | 9 |
| 2024 | 10 |
| 2023 | 3 |
| 2022 | 5 |
| 2021 | 9 |
| 2020 | 7 |
| 2019 | 4 |
| 2018 | 7 |
| 2017 | 5 |
| 2016 | 8 |
| 2015 | 4 |
| 2014 | 3 |
| 2013 | 2 |
| 2012 | 8 |
| 2011 | 6 |
| 2010 | 9 |
| 2009 | 1 |
| 2008 | 3 |
Source: Iowa Environmental Mesonet archive of National Weather Service watches, warnings and advisories (VTEC); National Weather Service. Data as of October 1, 2026.
When in the year does Delaware get them?
Sum of 2008-2025; the busiest month is labelled.
Source: Iowa Environmental Mesonet archive of National Weather Service watches, warnings and advisories (VTEC); National Weather Service. Data as of October 1, 2026.
Where in Delaware?
| County or forecast zone | Since 2008 | Since 2023 | Last issued |
|---|---|---|---|
| New Castle | 75 | 27 | September 3, 2026 |
| Inland Sussex | 65 | 17 | September 3, 2026 |
| Kent | 62 | 15 | September 3, 2026 |
| Delaware Beaches | 28 | 8 | July 15, 2026 |
The NWS issues these products for counties or forecast zones; a zone can be part of a county or a mountain range.
Source: Iowa Environmental Mesonet archive of National Weather Service watches, warnings and advisories (VTEC); National Weather Service. Data as of October 1, 2026.
What is a heat advisory?
A heat advisory means heat that can make people ill, especially those without cooling, below the office's extreme heat warning values. An advisory is issued for a hazard less serious than a warning that can still cause inconvenience or danger if people are not careful. The national record · Every warning type in Delaware.