- Onde
- ONDO Weather
- OnlinePro
- Ontario Air Quality
- OnTheSnow Ski & Snow Report
- Ontoto Connect
- Lightning Alarm
- OPEN I-STORMS
- OpenSnow: Weather Forecast
- OpenSprinkler
- OpenSummit
- OpenWeather
- OpenWind
- IBM Dashboard Visualization
- OPM DC Status
- OPU ENV Sensors Monitoring
- OPUS ONE SMART UMBRELLA JONAS
- Orai Lietuvoje
- ORBIS COMFORT-CONTROL
- Orai Lietuvoje
- ORBIS COMFORT-CONTROL
- Orbit: Sun Position
- Orbiter - Earth Visualizer
- OregonAir
- OrientElba
- OSHA-NIOSH Heat Safety Tool
- OSS Weather
- Oto App
- OurTheEarth:Genuine Earth as viewed from space
- Outside Now
- Overdrop - Weather & Widgets
- Owl Weather
- Oz Radar 2
- Oz Radar Lite
- Oz Radar TV
- Oz Radar Weather
- Oz Weather Plus