Download Cumulus here:
In Cumulus, select menu item Configuration / Internet.
Weather Underground Settings
Enabled - Tick this to allow Cumulus to upload data to Weather Underground at the interval specified in 'Interval' below.
Include UV - Causes UV value to be sent with the data.
Include Solar rad - Causes Solar Radiation value to be sent with the data.
Rapid fire - Tick this to enable 'rapid fire' mode. You should also tick 'Enabled'. Rapid fire updates occur every 5 seconds.
Station ID - Your Weather Underground station identifier (note: not your user name).
Password - The password for your weather station is no longer the same as the password for your wunderground.com account. It is now a separate key that is generated specifically for each Weather Underground station ID. You can find the station key/password associated with each weather station in your list of weather stations here:
Interval - Time in minutes between uploads to Weather Underground (Interval 5 mins).