What this workflow does
This workflow takes a place name from Slack and sends detailed weather forecasts back to a Slack channel automatically.
It solves the problem of manually searching weather and sharing it with a team by automating all steps.
The output is accurate weather information posted directly to Slack, saving daily time and avoiding delays.
Who should use this workflow
This workflow is for teams that need quick weather updates in Slack.
Project managers or event planners who want to send weather forecasts to their group without manual effort will find it useful.
Tools and services used
- n8n Workflow Editor: to build and run the automation.
- Slack OAuth2: posts messages to a Slack channel.
- Webhook node: receives location input from Slack.
- OpenStreetMap Nominatim API: converts location text to GPS coordinates.
- National Weather Service (NWS) API: gets weather grid data and forecasts.
How this workflow works
Inputs
The workflow starts when Slack sends a POST message with a location name to the Webhook node.
The location is in plain text inside the webhook body.
Processing Steps
- The OpenStreetMap HTTP Request node takes the location text and asks OpenStreetMap’s API for latitude and longitude.
- The NWS HTTP Request node uses that lat/lon to get a grid reference from the National Weather Service.
- The NWS1 HTTP Request node then requests the forecast from the grid points data.
- The Slack node formats the forecast into a readable message and sends it to a Slack channel.
Output
The result is a nicely formatted weather forecast in the Slack channel, showing temperature, wind, and a brief forecast for each period.
Beginner step-by-step: How to use this workflow in n8n
Importing the Workflow
- Download the workflow file using the Download button on the page.
- Open n8n editor and click on “Import from File”.
- Select the downloaded workflow file and import it.
Configuring Credentials and Settings
- Add Slack OAuth2 credentials to allow posting messages.
- Update the Slack node’s channel ID to the desired Slack channel.
- Set the User-Agent header in HTTP nodes with your email or identifier to meet API requirements.
Testing and Activation
- Send a test message with a location to the webhook URL or trigger the workflow to check if it returns weather data.
- If the test succeeds, activate the workflow to start automatic operation.
For running n8n on your own, review resources about self-host n8n.
Inputs, processing, and outputs details
Inputs
- Slack sends a location name in a POST webhook request.
Processing
- OpenStreetMap converts location text to latitude and longitude.
- NWS API converts lat/lon to weather grid details.
- NWS forecast API fetches detailed forecast for that grid.
- Slack node formats this forecast data into a message.
Outputs
- Slack channel receives a formatted weather forecast message with temperature, wind speed and direction, and short summary.
Common problems and how to fix them
- Failed to get data from NWS API:
Check if latitude and longitude are correct and JSON paths in the NWS HTTP node match the API response. - Slack message does not appear:
Make sure OAuth2 Slack credentials are valid and the Slack channel ID is correct. - Webhook does not start the workflow:
Ensure the webhook is active and its method and path match the Slack message sender.
Customization ideas
- Change the Slack channel ID in the Slack node to deliver messages where needed.
- Modify the Slack message format to add humidity or rain chances from the NWS forecast JSON.
- Add a decision node before OpenStreetMap to check the location text is valid and avoid bad API calls.
- Use a Schedule Trigger node instead of a webhook to send daily forecasts automatically.
Summary of results
✓ Saves daily time by automating weather lookup.
✓ Avoids delays or errors from manual sharing.
✓ Sends clear, updated weather forecasts directly to Slack.
→ Enables fast, easy weather info for teams before planning outdoor activities.