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Frequently Asked Questions

Data Availability​

Q: How much historical data is available in the API?​

A: The API provides access to the last 60 days of observation data. Any queries for data older than 60 days will return no results.

Q: Why do I sometimes get an empty response?​

A: There could be several reasons for empty responses:

  • Station offline: The weather station may be experiencing technical issues
  • Maintenance: Equipment may be undergoing scheduled maintenance
  • Data processing delays: Temporary delays in data transmission or processing
  • Query outside retention period: Requesting data older than 60 days

You will still receive a 200 OK status code with an empty results array in these cases.

Q: How often is the data updated?​

A: Observation data is collected and updated every minute from active weather stations, road sensors, and airport runway sensors.

Station Information​

Q: How do I find available weather stations?​

A: Use the /weatherStation endpoint to get a list of all stations that have reported at least one observation in the last 60 minutes, along with their metadata including location and identifiers.

Q: What's the difference between WMO and ICAO identifiers?​

A:

  • WMO ID: World Meteorological Organisation numeric identifier (e.g., 93110) - used for all station types
  • ICAO ID: International Civil Aviation Organization alphabetic identifier (e.g., NZKTA) - primarily used for airport/aviation stations

Both can be used interchangeably where available.

Q: Why don't all stations have the same variables?​

A: Different stations have different sensor configurations depending on their purpose:

  • Weather stations typically have comprehensive sensor suites
  • Road sensors focus on surface and atmospheric conditions relevant to transportation
  • Airport sensors prioritize aviation-specific measurements

API Usage​

Q: What's the difference between json and cf-json formats?​

A:

  • json (default): Standard JSON format with observation values
  • cf-json: Climate and Forecast compliant format that includes detailed field descriptions and metadata about each variable

Use cf-json when you need detailed information about what each field represents.

Q: How do I filter which variables are returned?​

A: Use the vars query parameter with a comma-separated list of variable names:

?vars=airtemp_01mnavg,windspd_01mnavg,rainfal_01mnacc

The obs_timestamp variable is always included regardless of filtering.

Q: What are the rate limits?​

A: Rate limits depend on your API account plan. If you exceed limits, you'll receive a 429 Too Many Requests response. Use the contact form for information about your specific limits.

Authentication & Access​

Q: How do I get API access?​

A: Send a request through the contact form with:

  • Your name and organization
  • Intended use case (commercial or non-commercial)
  • Expected request volume
  • Specific API requirements

Q: Can I use both API key and Bearer token authentication?​

A: Yes, the API supports both methods:

  • API Key: Include apikey: your-key in the request header
  • Bearer Token: Include Authorization: Bearer your-token in the request header

Choose the method that best fits your authentication infrastructure.

Technical Issues​

Q: What should I do if I get a 401 Unauthorized error?​

A: Check that:

  • Your API key or bearer token is correctly included in the request headers
  • Your API key hasn't expired
  • You have permission to access the requested station data
  • The header name is correct (apikey or Authorization)

Q: How should I handle 500 Internal Server Error responses?​

A: These indicate temporary server issues. Implement retry logic with exponential backoff. If errors persist, use the contact form for support.

Q: What's the maximum time range I can query at once?​

A: For range queries:

  • JSON format: Up to 1440 minutes (24 hours)
  • CF-JSON format: Up to 360 minutes (6 hours)

For larger datasets, make multiple requests with smaller time ranges.

Data Quality​

Q: How do I know if observation data is reliable?​

A: While the API doesn't include explicit quality flags, consider:

  • Recent observations are generally more reliable
  • Extreme values may indicate sensor issues
  • Missing variables may indicate sensor maintenance
  • Cross-reference with nearby stations for validation

Q: How are missing or invalid sensor values formatted in the API response?​

A: This depends on the format requested:

  • format=json (default): Missing or invalid values are returned as string placeholders "//" or "///". This preserves the raw sensor transmission representation, but requires downstream clients to handle these string values before parsing them as numeric types.
  • format=cf-json: Missing values are mapped to JSON null values in the variable data array (matching the variable's configured missing_value metadata property).

Q: What timezone are the timestamps in?​

A: All timestamps are in UTC (Coordinated Universal Time) and follow the RFC-3339 format (e.g., 2020-06-19T04:00:00Z).

Support​

Q: Who do I contact for technical support?​

A: For all API-related questions, technical issues, or access requests, contact: Contact form: data.metservice.com/contact

Include relevant details such as:

  • Your API key (first/last few characters only)
  • Specific endpoints and parameters used
  • Error messages received
  • Expected vs actual behavior