Sippican is introducing a new humidity sensing element and algorithm for its MKIIA radiosondes. A new capacitive sensor technology, replacing the resistive hygristor element, has improved accuracy throughout the temperature and humidity range. Worst case absolute errors are approximately ±5% RH. The new sensor also extends the temperature range by at least 15°C, providing reliable measured data at temperatures down below -55°C. Processing employs a simplified objective algorithm across all conditions.