Delaware heat wave risk
New Castle County has the highest heat wave risk in Delaware, scoring 95.3 out of 100 — rated "Relatively Moderate" by FEMA's National Risk Index. NOAA has recorded 24 heat wave events across Delaware over the past decade.
| # | County | NRI score | Rating |
NOAA events 2016–2026 |
|---|---|---|---|---|
| 1 | New Castle County | 95.3 | Relatively Moderate | 17 |
| 2 | Sussex County | 89.4 | Relatively Moderate | 3 |
| 3 | Kent County | 87.6 | Relatively Moderate | 4 |
Source: FEMA National Risk Index v1.20.0, December 2025. Scores are 0–100 percentile rankings among all US counties. See the methodology page for definitions. Download the full CSV for all counties.
Heat Wave risk nationally:
Other hazard risks in Delaware:
Frequently asked questions
What is the highest heat wave risk county in Delaware?
New Castle County, DE has the highest heat wave risk in Delaware, with a FEMA National Risk Index score of 95.3 out of 100 (rated "Relatively Moderate").
What causes heat wave risk in Delaware?
Heat is consistently the leading cause of weather-related mortality in the US, yet it remains underrepresented in federal disaster declarations relative to its actual impact. High scores reflect a combination of extreme temperature exposure, population vulnerability (elderly, outdoor workers), and limited access to cooling infrastructure.