Compound Signal
Heat Vulnerability
Extreme heat exposure × Heat-vulnerable population
50 counties are triggering this signal at the elevated threshold (≥70/100) right now.
County spotlight
Heat Vulnerability in Greenwood County, KS
2 days above 95°F against a heart-disease + diabetes prevalence of 9.4% + 14.4%.
Implicated population
~1,318
adults with heart disease or diabetes
What it measures
Where summer heat extremes converge with heart disease and diabetes prevalence and a cardiology access deficit. Heat is the single most-evidenced climate-health exposure (Lancet Countdown 2025: heat mortality up 23% since the 1990s); this signal flags where that exposure lands hardest.
Component breakdown
Each component is independently percentile-ranked against all US counties (0–100), then blended into the final signal score using the weights below.
| Component | Weight | Source |
|---|---|---|
| Avg summer max temperature | 40% | NOAA ACIS |
| CHD + Diabetes blend (60/40 dominant) | 30% | CDC PLACES |
| Cardiology access deficit | 30% | NPPES (inverted percentile) |
Evidence base
Heat-related mortality is dominated by cardiovascular events (Khatana et al, Circulation 2022 — heat-cardiac excess deaths +117% over a decade in high-heat counties). The dominant CHD/diabetes blend reflects the two chronic conditions most amplified by sustained heat exposure; the cardiology supply leg makes this a service-line indicator rather than a pure exposure-prevalence composite.
Khatana et al, Circulation 2022
Khatana SAM, Werner RM, Groeneveld PW. Association of extreme heat with all-cause and cause-specific mortality in the contiguous US, 2008–2017. Circulation. 2022;146:249–261.
Lancet Countdown 2025
The 2025 Report of the Lancet Countdown on Health and Climate Change. Heat-related mortality among older adults +23% since the 1990s.
Counties triggering this signal
Top 50 counties at the elevated threshold (70/100) or above, sorted by score. Click any county for the full profile.
Related service line: cardiovascular. The platform tool exposes per-county service-line opportunity scores on Pro, Studio, and Enterprise tiers.
Methodology
Every Compound Signal on this platform is a versioned, weighted composite published transparently. See the full methodology — every weight, every threshold, every data source — on the methodology page.
View full methodology →