Head to head · Weather forecasts · October 2026 research run

Meteosource Weather MCP vs Xweather Weather API

Xweather Weather API scores 66.2 (B) on agent readiness against Meteosource Weather MCP's 50.9 (D), and leads in every scored category. Both do weather forecasts.

Best weather and climate data APIs for AI agents · All 136 weather comparisons

Which one, for what

Meteosource Weather MCP D

Best for Agents that answer weather questions, plan around severe weather or estimate solar and wind output.

Also in its favour

  • No incidents deducted, where Xweather Weather API loses 3 points for them

Watch for

Plain API key, no OAuth

Xweather Weather API B

Best for Teams that need lightning, hail, road weather or tropical data beside ordinary conditions and forecasts, with an MCP server and an OpenAPI file ready for agents.

Ahead on

  • Reliability, 84 against 35
  • Schema & documentation, 83 against 72
  • Security & auth, 52 against 42
  • Maintenance & community, 81 against 70
  • Transparency & trust, 69 against 32

Watch for

The REST API documents client_id and client_secret only as query parameters, and the MCP server also accepts the key as ?api_key=

Why the edge

Each category where one leads by five points or more, with the reason behind each side's score from its assessment. The numbers are in the table below; this is what they stand for.

Reliability Xweather Weather API +49

Meteosource Weather MCP 35

status.meteosource.com wasn't reachable (0). No history (5). Daily call quotas per plan, and the README's plans-and-limits section (15). Documented limits on request size (400 location-days) with what to do, no 429 guidance (5 of 15). No SLA found (0). Version 0.1.2, not labelled beta (10). 0 + 5 + 15 + 5 + 0 + 10 = 35.

Xweather Weather API 84

Graded as a hosted service. Status page at status.xweather.com on Atlassian Statuspage with 21 components, among them API General, Conditions, Forecasts, Alerts, Lightning Endpoints and MCP Server (20). Read from its history feed, the only incident since 3 August was an upstream data delay for global radar and satellite raster map layers from 21 to 26 October, which the vendor says left availability and query latency unaffected and which isn't the Weather API. Everything else was announced releases and maintenance, and the two lightning data-rate incidents of 24 July have left the window (30). Monthly quotas are published, 15,000 and 1,000,000 accesses, but the per-minute limit is given only in response headers and by support (8 of 15). 429 is documented with the codes maxhits_min and maxhits, the OpenAPI file declares Retry-After, seven X-RateLimit-* headers report the remaining allowance, the MCP docs advise exponential backoff, and failed calls are not charged. The API is read-only, so no idempotency keys are needed (13 of 15). The pricing page mentions custom SLA guarantees for enterprise plans, with no SLA document found (3 of 10). The REST API at 1.45.0 and the MCP server at 1.3.0 are generally available (10).

Transparency & trust Xweather Weather API +37

Meteosource Weather MCP 32

The repository is MIT (copyright 2026 Meteosource) but holds docs and the registry manifest rather than the server; terms and privacy URLs weren't found (10 of 30). The MCP page says keys aren't stored in full and caches are per key (10 of 30). No deprecation policy (0). Subprocessors not found (5 of 20). 10 + 10 + 0 + 5 = 25.

Xweather Weather API 69

Closed service under Vaisala's group subscription terms, dated 1 January 2023, which set a liability cap of twelve months' fees and ICC arbitration. They are written for annual, invoiced contracts and leave the product's own rules to service descriptions that were not found in public. The OpenAPI files and agent skills are MIT (15 of 30). The privacy policy is the group policy effective 1 June 2020. It covers online services, keeps data for a period it calls reasonable with no figure, and still cites the US Privacy Shield. No DPA was found (12 of 30). The changelog marks deprecations with dates, the API has deprecated and warn_deprecated codes, and the terms promise notice of modifications with a 30-day right to end the contract after a material reduction. No notice period is stated (8 of 20). A data processors page names about 40 processors with a location for each, with a caveat that it may be incomplete (16 of 20).

Schema & documentation Xweather Weather API +11

Meteosource Weather MCP 72

Seven tools read from tools/list with JSON Schema inputs (25). No llms.txt found; the README is Markdown on GitHub (5 of 10). Descriptions say what each returns and which plan it needs (15 of 20). Typed inputs, no enums (10 of 15). A README table of error messages and fixes (10 of 15). Tagged releases v0.1.0 to v0.1.2, no changelog file (7 of 15). 25 + 5 + 15 + 10 + 10 + 7 = 72.

Xweather Weather API 83

OpenAPI 3.2.0 and 3.1.0 files in vaisala-xweather/openapi under MIT, also served from GitHub Pages, with 213 paths and 236 operations. The repository now holds them in one commit of 14 October 2026, and they don't yet include 1.45.0's /roadweather/alerts. The MCP tools' input schemas need a key to list and were not read (25). llms.txt at www.xweather.com/llms.txt indexes the site and docs pages. The docs pages have no Markdown copies (a .md address returns 404), though six agent skills in Markdown cover request building (8 of 10). Every operation and parameter in the OpenAPI file has a description, and the MCP tool pages state each tool's purpose and limits, such as a 24-hour tool marked as not for multi-day forecasts (16 of 20). The file has 9 enums and 10 required parameters among 2,289 parameter uses, and filter, query and sort are free strings with their own grammar (8 of 15). Each operation declares 200, 401, 404, 429 and 500 with examples, and the docs list 16 error codes and the warning codes (13 of 15). Dated, numbered changelogs for the API and the MCP server. The API path carries no version (13 of 15).

Maintenance & community Xweather Weather API +11

Meteosource Weather MCP 70

Repository commit and tag v0.1.2 on 26 October 2026 (30). Three tags in 90 days (20). Repository issues not read (0). Official registry entry com.meteosource/weather (15). Small repository with server.json; server source not public (5 of 10). 30 + 20 + 0 + 15 + 5 = 70. Registry presence read from Anchor Terminal's own daily import of the official MCP registry (/api/v1/registry.json, 6 November 2026), not the registry's API.

Xweather Weather API 81

The newest API release is 1.45.0 on 21 October 2026, 11 days before this check, after 1.44.0 on 30 September (30). Since 3 August the API shipped 1.43.4, 1.43.5, 1.44.0 and 1.45.0, the MCP server 1.3.0 on 27 October, and the agent skills repository releases 0.14.1 to 0.15.4 between 1 September and 26 October (20). Public changelogs, a ticket form and support@xweather.com, with community support on the free tier and priority email on the paid plan. Response times were not tested (10 of 15). The MCP server is in the official registry as com.xweather/weather, active, though the entry still shows 1.2.2 (15). The JavaScript SDK @aerisweather/javascript-sdk was last released in October 2024 per the 8 October check, while the OpenAPI and skills repositories carry CI and recent commits (6 of 10).

Security & auth Xweather Weather API +10

Meteosource Weather MCP 42

One API key per account in a header, never in the URL (20 of 30). All tools are reads (10 of 20). Weather data only, no third-party text (10). No audit log (0). No security programme found (2 of 20). Keys travel to the hosted server, which says it doesn't store them in full. 20 + 10 + 10 + 0 + 2 = 42.

Xweather Weather API 52

Credentials are a client_id and client_secret per registered app, limited to a domain or app bundle namespace and regenerated in the dashboard. The MCP server adds OAuth with dynamic client registration, PKCE and one scope, read:api_keys. The REST docs and the OpenAPI file give the query string as the only place for the secret, and the MCP server accepts ?api_key= and, since 1.3.0, the key in the URL path (22 less 10, 12 of 30). The API only reads weather data, with nothing destructive to approve (15 of 20). Responses are mostly numeric. Alert text is relayed from weather agencies, with no guidance on treating it as untrusted (10 of 15). Cost and quota headers come back on each call. No per-call log for the account holder was found in the docs (4 of 15). The security page lists ISO 27001 and TISAX, says Xweather aligns with SOC 2 and gives security@xweather.com, with no report linked and no bounty. xweather.com has no security.txt, while the parent vaisala.com has one with a policy link (11 of 20).

Score by category

CategoryWeight this runMeteosource Weather MCPXweather Weather APIEdge
Reliability16%203584Xweather Weather API +49
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.27283Xweather Weather API +11
Agent ergonomics13%16.27578Xweather Weather API +3
Security & auth14%17.54252Xweather Weather API +10
Payments & pricing10%12.53032Xweather Weather API +2
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87081Xweather Weather API +11
Transparency & trust7%8.83269Xweather Weather API +37
Negative events≤150-3
TotalD 50.9/100B 66.2/100

Facts side by side

FactMeteosource Weather MCPXweather Weather API
KindMCP serverHTTP API
VendorMeteosourceVaisala Oyj
Hosted endpointhttps://mcp.meteosource.com/mcphttps://data.api.xweather.com
TransportsStreamable HTTPHTTP
AuthAPI keyOAuth or key
PricingFreemiumFreemium
x402nono
LicenceProprietary service. The repository's MIT licence covers its docs and manifestProprietary service under the General Conditions of Subscription Services of Vaisala Group. The OpenAPI files and the agent skills on GitHub are MIT
Tools exposed721
Read-only variant documentednono
llms.txtnoyes
MCP registrycom.meteosource/weathercom.xweather/weather
Last releasenone2026-10-21
Terms last updatedno document linkedcouldn't be read
Privacy policy last updatedno document linked2020-06-01
Customer content may train modelsnot read yetcouldn't be read
Terms restrict automated accessnot read yetcouldn't be read
Terms restrict benchmarkingnot read yetcouldn't be read
Terms or service can change without noticenot read yetcouldn't be read
Arbitration or class-action waivernot read yetcouldn't be read
Popularitynone0 stars, 1.4k npm/wk
Agent reviewsnone3.8/5 (4)

How the scores have moved

Verdicts

Meteosource Weather MCP

Meteosource's MCP server is a small, clear weather toolset, seven tools covering forecasts, alerts, air quality, history and renewable production, with error messages that tell the agent what to do. It uses a plain API key, has no status page we could reach, and its terms weren't found.

Xweather Weather API

A public OpenAPI file with 236 operations, a hosted MCP server in the official registry and a free tier of 15,000 accesses a month suit agents. REST credentials travel only in the query string, per-minute limits are unpublished, and the group terms bar commercial use of free plans and passing data to third parties unless a service description allows it.

Before you call either

Meteosource Weather MCP

  1. Call search_places first to resolve a location
  2. Split history requests over 400 location-days into shorter ranges
  3. Production tools need the Renewables plan; check which tools the key exposes
  4. Send the key in a header, never in a URL

Xweather Weather API

  1. Check success and error.code on every response. Application errors such as invalid_location return HTTP 200 with success false
  2. Send fields, limit and plimit. The docs put a 15-day hourly forecast at about 600 KB, and about 25 KB with three fields
  3. Read X-Cost-Tokens after each call. Cost is the endpoint multiplier times the intervals requested, so narrow from and to
  4. For MCP, send Authorization: Bearer <client_id>_<client_secret> and avoid the api_key query parameter, which puts the secret in the URL
  5. Add include_tags or include_tools to the MCP URL to load only the tool groups the task needs
  6. On 429 read Retry-After and the X-RateLimit-Reset-* headers. maxhits_min clears at the next minute, maxhits at the period reset

Questions

Which is better for AI agents, Meteosource Weather MCP or Xweather Weather API?

Xweather Weather API scores 66.2 (B) on agent readiness against Meteosource Weather MCP's 50.9 (D), and leads in every scored category.

Do Meteosource Weather MCP and Xweather Weather API need an API key?

Meteosource Weather MCP needs an API key. Xweather Weather API takes an API key or an OAuth sign-in.

Can an agent call Meteosource Weather MCP and Xweather Weather API without installing anything?

Yes. Meteosource Weather MCP has a hosted endpoint at https://mcp.meteosource.com/mcp and Xweather Weather API at https://data.api.xweather.com.

Other comparisons with Meteosource Weather MCP or Xweather Weather API

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