ClimatologyClimatology PlugIn for OpenCPN 4.x.x

Provides overlay capabilities for historic weather data.
Supported Climatology types include:

Average wind directions and speed
Percentage of gale and calm conditions
Average swell and seastate (not yet implemented)
Precipitation, Humidity, and Cloud Cover
Monthly average Sea Level pressure and Sea Temperature, Air Temperature
Tropical Cyclone tracks

http://opencpn.org/ocpn/downloadplugins
Source
https://github.com/seandepagnier/climatology_pi