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Weather · head to head

OpenWeatherMap vs PurpleAir

OpenWeatherMap logo

OpenWeatherMap

Weather

Developer-friendly weather API with global coverage

From
Free
Rated
-
Full reviewWebsite
PurpleAir logo

PurpleAir

Weather

Real-time air quality monitoring for communities

From
$229/one-time
Rated
-
Full reviewWebsite

The short version

  • Only OpenWeatherMap has a free tier, so it costs nothing to try first.
  • Each has a real cost: OpenWeatherMap free tier capped at 60 calls/minute and 1,000,000 calls/month; PurpleAir purpleAir sensors are one-time hardware purchases rather than a subscription, priced $199 to $279 USD per unit for named models (PA-I-Indoor, PA-II, PA-II-SD), per the vendor's own store (archived, 2021).
  • They diverge on capability: OpenWeatherMap covers Weather API, PurpleAir covers PM2.5 monitoring.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which OpenWeatherMap and PurpleAir actually diverge.

Attributes where OpenWeatherMap and PurpleAir differ
AttributeOpenWeatherMapPurpleAir
Starting priceFree$229/one-time
Pricing modelfreemiumone-time
Free tierYesNo
PlatformsWebWeb, Api, Hardware
Founded20172015

Identical on both: user rating (Not yet rated), category (Weather).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in OpenWeatherMap

  • Weather API
  • Current conditions
  • Forecasts
  • Weather maps
  • REST API
  • JSON format
  • Widgets

Only in PurpleAir

  • PM2.5 monitoring
  • Real-time map
  • Community network
  • API access
  • API access
  • Home Assistant
  • Data downloads
  • Hardware support

Both cover

  • Historical data
  • Api support
  • Web support

What people use each for

The jobs each tool is most often brought in to do.

OpenWeatherMap

  • Embedding current weather and short-term forecasts into third-party apps/websitesnot PurpleAir
  • Pulling historical and statistical weather data for researchnot PurpleAir
  • Displaying weather map overlays (precipitation, clouds, etc.) via the Weather Maps APInot PurpleAir
  • Monitoring air pollution levels via the Air Pollution APInot PurpleAir
  • Geocoding locations for weather lookupsnot PurpleAir

PurpleAir

  • Professional Worknot OpenWeatherMap
  • Content Creationnot OpenWeatherMap

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

OpenWeatherMap

  • Free tier capped at 60 calls/minute and 1,000,000 calls/month
  • Free tier limited to current weather, 3-hour/5-day forecast, air pollution, 15 map layers, and geocoding only
  • One Call API free allowance is only 1,000 calls/day before pay-per-call charges apply
  • Paid tier (Startup, Developer, Professional, Expert) exact USD prices are not published on the public pricing page

PurpleAir

  • PurpleAir sensors are one-time hardware purchases rather than a subscription, priced $199 to $279 USD per unit for named models (PA-I-Indoor, PA-II, PA-II-SD), per the vendor's own store (archived, 2021).

Pricing, plan by plan

OpenWeatherMap

Free
  • FreeFree
    • 1,000 free API calls per day

PurpleAir

$229/one-time
  • Outdoor Sensor$229/one-time
    • PM2.5 monitoring
    • Cloud connectivity
    • Map access
  • Indoor Sensor$199/one-time
    • Indoor monitoring
    • WiFi enabled
    • Real-time data

Which should you pick?

Choose OpenWeatherMap if

  • You need weather api.
  • You want to start without paying.
  • You also want current conditions.
OpenWeatherMap review

Choose PurpleAir if

  • You need pm2.5 monitoring.
  • You work on Web, Api, Hardware.
  • You also want real-time map.
PurpleAir review

Questions people ask

Is OpenWeatherMap or PurpleAir better?
Neither clearly leads. OpenWeatherMap starts at Free and PurpleAir at $229/one-time, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, OpenWeatherMap or PurpleAir?
OpenWeatherMap has a free tier; the other does not. Paid plans start at Free for OpenWeatherMap and $229/one-time for PurpleAir.
Does OpenWeatherMap or PurpleAir run on more platforms?
OpenWeatherMap runs on Web. PurpleAir runs on Web, Api, Hardware.
Can I use OpenWeatherMap for free?
Yes. OpenWeatherMap has a free tier, so you can try it without paying. PurpleAir starts at $229/one-time.
What is OpenWeatherMap best used for?
OpenWeatherMap is most often used for embedding current weather and short-term forecasts into third-party apps/websites, pulling historical and statistical weather data for research, displaying weather map overlays (precipitation, clouds, etc.) via the weather maps api, monitoring air pollution levels via the air pollution api. Of those, embedding current weather and short-term forecasts into third-party apps/websites and pulling historical and statistical weather data for research are not what PurpleAir is typically brought in for.
What can OpenWeatherMap do that PurpleAir cannot?
OpenWeatherMap covers Weather API, Current conditions, Forecasts, Weather maps. PurpleAir covers PM2.5 monitoring, Real-time map, Community network, API access. Both handle Historical data, Api support, Web support.

Answered from the vendors’ own pages

OpenWeatherMap: How much does OpenWeatherMap cost?

OpenWeatherMap operates on a pay-as-you-call usage-based pricing model. The platform offers a free tier with 1,000 API calls per day, and customers can purchase additional calls based on their needs.

Source
OpenWeatherMap: Is there a free weather API service?

Yes. OpenWeatherMap provides a free tier that includes up to 1,000 API calls per day. Users can subscribe for free at home.openweathermap.org without providing payment information.

Source
OpenWeatherMap: Does OpenWeatherMap offer enterprise plans?

OpenWeatherMap offers separate service tiers for enterprise customers, with pricing and features determined on a case-by-case basis. Contact the company directly for enterprise plan details and custom pricing.

Source
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