Weather NWS
US weather forecasts via National Weather Service (NWS) with automatic fallback to global weather for non-US locations. Provides detailed accumulation data,...
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License
Runtime requirements
AIRNOW_API_KEYoptional— AirNow API Key for AQI lookupSKILL.md
Weather NWS Skill
Get detailed US weather forecasts from the National Weather Service with automatic global fallback, hourly forecasts, air quality data, and structured winter storm accumulations.
What This Skill Does
This skill operates in 8 modes to match your query:
| Mode | When It Activates | What You Get |
|---|---|---|
| 🌦️ Standard Forecast | Default (no time specified) | 12-hour forecast with today/tonight/tomorrow |
| ⏰ Hourly Forecast | Time-specific query detected | Hour-by-hour breakdown (~156 periods, 7 days) |
| 🌨️ Winter Storm | Keywords like "snow," "storm" | 12-hour + structured accumulation data |
| 💨 AQI Report | --aqi flag included | Current + forecast air quality index |
| 🌡️ Observed vs Forecast | --current flag included | Current station readings with comparison |
| ☀️ Astronomical Times | --astro flag included | Sunrise/sunset, twilight, moon phase |
| ✈️ Aviation Forecast | --taf flag included | Terminal Aerodrome Forecast (TAF) |
| 🔥 Fire Weather | --fire flag included | Fire danger, red flag warnings |
| 🌍 Global Fallback | Non-US location | wttr.in data (less detailed) |
AirNow API Key (Optional but Recommended)
The AirNow API works without a key but has limitations:
| Without API Key | With API Key |
|---|---|
| Rate limited (requests may fail) | Higher rate limits |
| No guaranteed availability | Priority access |
| May return empty results | Reliable AQI data |
Getting an API Key
- Visit: https://docs.airnowapi.org/account/request/
- Fill out the request form (free for personal use)
- Key arrives via email within 1-2 business days
Setting the API Key
Option 1: Environment Variable (Recommended)
export AIRNOW_API_KEY="your-api-key-here"
Option 2: OpenClaw Config (Persistent)
Add to your OpenClaw config under skills.entries.weather-nws.env:
{
"skills": {
"entries": {
"weather-nws": {
"env": {
"AIRNOW_API_KEY": "your-api-key-here"
}
}
}
}
}
When to Use
✅ USE this skill when:
- "What's the weather in [US city]?"
- "How much snow is expected?"
- "Winter storm forecast for [location]"
- "Will it rain tomorrow in [US city]?"
- "What time will the rain stop?"
- "Air quality in [city] today"
- Any US-based weather query
🔄 Automatic fallback:
- Non-US locations → wttr.in
- NWS API unavailable → wttr.in
- Both sources fail → clear error message
Quick Start
# Run the unified weather script
python3 ./scripts/get_weather.py "New York, NY"
# Force specific source if needed (normally auto-detected)
python3 ./scripts/get_weather.py "London, UK" --source wttr
# Get hourly forecast (auto-detected or forced)
python3 ./scripts/get_weather.py "Boston at 8 PM"
python3 ./scripts/get_weather.py "Chicago" --hourly
# Include air quality
python3 ./scripts/get_weather.py "Seattle" --aqi
Hourly Auto-Detection
The skill automatically detects time-specific language and switches to hourly forecast:
"Boston at 8 PM" → ⏰ Hourly mode
"Boston tonight" → ⏰ Hourly mode
"Boston tomorrow morning" → ⏰ Hourly mode
"Boston at 5:30" → ⏰ Hourly mode
"When will it stop raining?" → ⏰ Hourly mode
Patterns detected:
at 8 PM,at 5:30, etc.tonight,this afternoontomorrow morning/afternoon/nightwhen will...,how long until...
Air Quality (--aqi)
Adds AirNow AQI data to any forecast:
python3 ./scripts/get_weather.py "Boston" --aqi
Output includes:
- Current AQI with color-coded emoji (🟢 🟡 🟠 🔴 🟣 🔵)
- Primary pollutant (PM2.5, O3, etc.)
- Health recommendation based on category
- 3-day AQI forecast
AQI Categories:
| Range | Category | Emoji | Recommendation |
|---|---|---|---|
| 0-50 | Good | 🟢 | Enjoy outdoor activities |
| 51-100 | Moderate | 🟡 | Sensitive groups limit exertion |
| 101-150 | Unhealthy for Sensitive Groups | 🟠 | Children/elderly limit outdoor activities |
| 151-200 | Unhealthy | 🔴 | Everyone reduce outdoor exertion |
| 201-300 | Very Unhealthy | 🟣 | Avoid outdoor activities |
| 301-500 | Hazardous | 🔵 | Stay indoors — health alert |
Output Format
The script provides consistent output regardless of source:
Header: Location and current alert status Today → Tonight → Tomorrow: Structured timeline Accumulation: Specific snow/rain amounts when available Bottom Line: Actionable summary with timing
Implementation
The script handles:
- Geocoding location to lat/long
- Detecting if location is in US
- Calling NWS API for US locations (detailed accumulation)
- Falling back to wttr.in for non-US (basic forecast)
- Formatting consistent output with emojis and structure
Limitations
- NWS: US only, requires internet, rate limited
- wttr.in: Global, less detail on accumulation, no official watches/warnings
- AirNow: US + Canada only, requires API key for reliable access
Examples
US winter storm query:
python3 ./scripts/get_weather.py "Boston, MA"
→ Returns NWS data with accumulation estimates
International location:
python3 ./scripts/get_weather.py "Toronto, Canada"
→ Automatically uses wttr.in, notes it's non-US
With air quality:
python3 ./scripts/get_weather.py "Seattle" --aqi
→ Weather + AQI data with health recommendations
Observed vs Forecast:
python3 ./scripts/get_weather.py "Boston" --current
→ Current station readings with forecast comparison
Combined features:
python3 ./scripts/get_weather.py "Seattle" --aqi --current
→ Full weather report with all data sources
Phase 3 features:
python3 ./scripts/get_weather.py "Boston" --astro # Sunrise/sunset times
python3 ./scripts/get_weather.py "SFO" --taf # Aviation forecast
python3 ./scripts/get_weather.py "California" --fire # Fire weather
python3 ./scripts/get_weather.py "Denver" --astro --aqi --current # Everything!
Observed vs Forecast (--current)
Shows actual measured conditions from the nearest NWS observation station alongside the forecast:
🌡️ **Observed Conditions**
**Actually 43°F (3° warmer than 40° forecast)**
☁️ Partly Cloudy
💨 WNW 8 mph • 💧 36% humidity • 🌫️ Dewpoint 18°F • 📊 Pressure 29.86 inHg • 👀 Visibility 10+ mi
Fields shown:
- Temperature with forecast delta
- Conditions description
- Wind speed and direction
- Humidity percentage
- Dewpoint
- Barometric pressure (inHg)
- Visibility
Alert Priorities
When alerts are active, they're displayed with enhanced formatting using severity/urgency/certainty weighting:
| Factor | Weights |
|---|---|
| Severity | Extreme (4) > Severe (3) > Moderate (2) > Minor (1) |
| Urgency | Immediate (3) > Expected (2) > Future (1) |
| Certainty | Observed (3) > Likely (2) > Possible (1) |
Severity Styling:
| Severity | Emoji | Badge |
|---|---|---|
| Extreme | ⚫ | EXTREME |
| Severe | 🔴 | SEVERE |
| Moderate | 🟠 | MODERATE |
| Minor | 🟡 | MINOR |
Alert display includes:
- Event name with severity badge
- Urgency tag: ⏰ Immediate / 📅 Expected / 🔮 Future
- Time range (onset → expires)
- First sentence of description
- Recommended response action
Example:
🟠 [**MODERATE**] **Winter Storm Warning**
📅 Expected | *Winter Storm Warning from 6 PM to 10 AM EST*
🕐 6:00 PM → 10:00 AM
📝 Heavy snow expected with accumulations of 6-10 inches...
👉 🎒 Prepare now
References
- references/nws-api.md — NWS API endpoint details
- references/airnow-api.md — AirNow API documentation
Phase 3 Features
Astronomical Times (--astro)
Shows sunrise, sunset, civil twilight, and moon phase information:
python3 ./scripts/get_weather.py "Boston" --astro
Output includes:
- 🌅 Sunrise: Time with countdown/ago
- 🌇 Sunset: Time with countdown/ago
- 💡 Civil Twilight: Dawn and dusk times (useful for runners, cyclists)
- ⏱️ Daylight: Total hours of daylight
- 🌙 Moon: Current phase with illumination percentage
Example:
☀️ **Astronomical Times — Boston**
🌅 **Sunrise:** 6:22 AM (12h ago)
🌇 **Sunset:** 5:31 PM (in 2h)
💡 **Civil Twilight:** 5:55 AM – 5:58 PM
⏱️ **Daylight:** 11h 9m
🌙 **Moon:** 🌓 First Quarter (50.0%)
Aviation Forecast (--taf)
Shows Terminal Aerodrome Forecast (TAF) for the nearest aviation weather station:
python3 ./scripts/get_weather.py "SFO" --taf
Note: TAFs are designed for aviation use. The report provides:
- Station identifier
- Wind conditions and direction
- Visibility
- Cloud ceiling information
Important: This is informational only. Always check official sources for flight planning.
Fire Weather (--fire)
Shows fire danger information for wildfire-prone areas:
python3 ./scripts/get_weather.py "California" --fire
Output includes:
- Fire danger level (if elevated)
- 🔥 Red Flag Warnings (if active)
- Fire weather zone forecast
- Source attribution
Red Flag Warnings indicate critical fire weather conditions (low humidity + high winds).
Changelog
v1.3.0 (2026-02-26) - Phase 3
- Added
--astroflag for sunrise/sunset, twilight, and moon phase - Added
--tafflag for Aviation Terminal Aerodrome Forecasts - Added
--fireflag for fire weather danger and red flag warnings - Added moon phase calculation (waxing/waning, illumination %)
- Added daylight hours calculation
- Added civil twilight detection for runners/cyclists
v1.2.0 (2026-02-26) - Phase 2
- Added
--currentflag for station observations vs forecast comparison - Enhanced alert formatting with severity/urgency/certainty priority scoring
- Added temperature delta comparison (warmer/cooler than forecast)
- Added full observation details: humidity, dewpoint, pressure, visibility
v1.1.0 (2026-02-26)
- Added hourly forecast with temporal query auto-detection
- Added AirNow AQI integration (
--aqiflag) - Added structured grid data for winter storm accumulations
- Fixed AirNow API endpoint URLs
v1.0.0 (2026-02-22)
- Initial release: NWS API with wttr.in fallback
- 12-hour forecast periods
- Alert integration
- Accumulation estimates from text parsing
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