Look at the METAR data pilots use for an example of how easily weather data can be compressed. KSEA 020153Z 34008KT 10SM FEW075 OVC090 18/14 A2997 Here's the

Look at the METAR data pilots use for an example of how easily weather data can be compressed. KSEA 020153Z 34008KT 10SM FEW075 OVC090 18/14 A2997 Here's the local conditions at Sea-Tac at 7:15pm Pacific time. We have wind direction and speed, visibility, cloud conditions, temperature and dew point and barometric pressure in one small snippet. The forecast data for the next 24 hours is given similarly. Radar data would be more complex but the basics for any weather app are only a handful of bytes.