Downloading Clear Day 3.1 for Mac from the developer's website was possible when we last checked. We cannot confirm if there is a free download of this app available. We recommend checking the downloaded files with any free antivirus. This software for Mac OS X is an intellectual property of vimov, LLC. The application belongs to Lifestyle Tools.
From the developer:
Clear Day (was Weather HD), the iPhone and iPad's top-selling weather application, brings the stunning beauty and design of Weather HD tailored and specifically designed for OS X. Features: Weather forecasts in more than 150,000 locations around the world. Stunning high-definition animations that depicts the weather conditions. Severe Alerts in the U.S. and Europe. Weather maps and Moon phases. Customizable notifications.
You may want to check out more Mac applications, such as Clear Day - Formerly Weather HD, My Wonderful Days : Daily Journal/Diary or Countdown Days, which might be related to Clear Day.