Turn any weather condition into a signed webhook — edge-triggered, delivery-guaranteed, observable.
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How it works
Define your rule in JSON — any combination of temperature, wind, precipitation, or probability conditions over a time window.
wettr.xyz polls the forecast on your schedule. When the rule transitions from false → true, a unique event is created — exactly once.
Your endpoint receives a signed POST request with full event context. Failed deliveries retry automatically — up to 5 attempts.
Payload
Each webhook includes the full rule context, location, and a signature header you can verify in one line.
{
"event_id": "evt_01HX3R7NKQWP8ZMD4BVC6YG5TA",
"alert_id": "alt_01HX1K9MFPQR3WBE7NJT2XC8SL",
"triggered_at": "2025-01-15T09:00:00Z",
"location": {
"lat": 47.6062,
"lon": -122.3321,
"label": "Seattle, WA"
},
"rule": {
"operator": "AND",
"conditions": [
{
"metric": "wind_speed_kmh",
"comparison": "GT",
"value": 60,
"window_hours": 6
},
{
"metric": "precipitation_mm",
"comparison": "GTE",
"value": 10,
"window_hours": 6
}
]
},
"matched_forecast": {
"time": "2025-01-15T11:00:00Z",
"temperature_c": 7.2,
"wind_speed_kmh": 74.1,
"precipitation_mm": 12.8,
"precip_probability_pct": 95
}
}Features
Fires once when a condition becomes true — not on every evaluation. Your automation responds to the moment of change, not the steady state.
Every webhook includes X-Wettr-Signature for
verification. One HMAC_SHA256 check and you know
the payload is authentic.
Every delivery attempt is logged — status code, latency, error message. Know exactly what happened to every event, without digging through your own logs.
Configure a cooldown window per alert. Even if the weather oscillates, your webhook fires at most once per cooldown period — keeping your automation quiet when it should be.
Pricing
All plans include HMAC signing, delivery logs, and retry backoff.
Starter
Pro
FAQ
The initial release supports four metrics: temperature (°C), wind speed (km/h), precipitation (mm), and precipitation probability (%). You can combine them with AND/OR logic and specify a time window (e.g., "any point in the next 6 hours"). More metrics — UV index, humidity, snow depth — are on the roadmap.
wettr.xyz tracks the previous evaluation state for each alert. A webhook fires only when the rule transitions from false → true. If wind speed stays above your threshold for 12 hours, you get exactly one webhook — at the moment it crossed the threshold. The event won't repeat until the condition clears and fires again. The optional cooldown window gives you additional control.
Forecasts are sourced from Open-Meteo, a high-resolution open-source weather API that aggregates multiple global models (ECMWF, GFS, and others). It offers 1 km resolution for some regions and sub-hourly updates. Accuracy varies by location and forecast horizon, as with any weather service — wettr.xyz provides the trigger infrastructure, not the forecast itself.
wettr.xyz retries failed deliveries on a backoff schedule: immediately, then +1 min, +5 min,
+15 min, and +60 min. After 5 attempts, the delivery is marked failed
and logged. Every attempt — status code, latency, error — is visible in your delivery log.
The same event_id is preserved across retries,
so your endpoint can safely deduplicate.
Join the waitlist — we'll let you know the moment we launch.