NWS active alerts API (api.weather.gov): what it returns, and whether it works in Clay

NWS active alerts API (api.weather.gov) is not available in Clay. It is best for Buying signals, Monitoring. Pricing: Free. Access: Free, no key (User-Agent required); rate limits exist but are not published, with retry after about 5 seconds when exceeded. Licence: open data for any purpose per NWS..

Data domains: Government, Weather, Geography, Signals.

What does NWS active alerts API (api.weather.gov) return?

Official fields (alert properties read from a live response): id; areaDesc; geocode (SAME and UGC codes); affectedZones; references; sent; effective; onset; expires; ends; status; messageType; category; severity; certainty; urgency; event; sender; senderName; headline; description; instruction; response; parameters (for example hail size and wind gust on warnings); scope; code; language; web; eventCode; plus polygon geometry for storm-based warnings. 493 active alerts at check.

What can you derive from it?

1. Live warning polygon: severe thunderstorm and tornado warnings with hail and wind parameters, the earliest signal of damage. 2. Winter storm and freeze warnings: demand for burst pipe, HVAC and plumbing calls. 3. Extreme heat warnings: AC failure and HVAC emergency demand. 4. Flood warnings by county: water damage restoration demand. 5. Warning count per territory per week: a running demand index for home-services branches.

How would a GTM team use it?

1. Revenue trigger: when a hard freeze warning covers a plumbing portco's territory, schedule pre-freeze outreach and staff the phones. 2. Monitoring: push tornado and extreme wind warnings that touch portfolio sites to operations leads. 3. HVAC campaigns: start AC tune-up and replacement ads when extreme heat warnings are issued. 4. Content demo: show how many hours of warning a roofer gets before hail reports appear. 5. Diligence: correlate a target's call volume with warning days to size weather sensitivity.

What are the caveats?

Not a native Clay integration as of 2026-10-17 (checked against Clay's integrations catalog). Can be called through Clay's HTTP API column where an API exists. Warnings are forecasts of risk, not confirmed damage; pair with SPC reports or outage data. Alerts expire, so archive them yourself or use the seven-day /alerts endpoint. Zone-based alerts cover whole counties or forecast zones; only storm-based warnings carry tight polygons. NWS plans to replace the User-Agent rule with API keys.