Skip to main content
Skip to footer
About
Our Organization
About the IES
Diversity & Inclusion
Society Awards
Administration
IES Staff
IES Board
IES Committees
Information
Newsroom
Annual Report
Resources
Membership
Membership
Join
Committees & Panels
Sustaining Membership
Emerging Professionals
University Program
Member Directory
Section Directory
Section Resources
Volunteer Opportunities
Philanthropic Donations
Events
Information
Events Calendar
Sponsorship
IES Progress Report
Featured Events
Light + Justice Symposium
IES24 Conference
Street & Area Lighting Conference
Research Symposium
Special Events
Light for Life®: Museum Symposium
Illumination Awards & Gala
Lighting Education Tour
Aviation Lighting Conference
Research & Education
Research
About IES Research
Publications
FIRES Forum
Past Projects
IES Lighting Ready Reference App
Education
eLearning Portal
Upcoming Webinars
Request IES CEU/AIA-LUs
LC Study Group
Register Now for Our Next Webinar
Standards
Standards
Purchase Standards
Browse Standards
Nomenclature & Definitions
Standards Errata & Addenda
Information
What’s New
Standards Process
Standards in Public Review
Toolbox
IES Standards Toolbox
My Lighting Library
My Illuminance Selector
My Reference Retriever
LD+A
Store
About
Our Organization
About the IES
Diversity & Inclusion
Society Awards
Administration
IES Staff
IES Board
IES Committees
Information
Newsroom
Annual Report
Resources
Membership
Membership
Join
Committees & Panels
Sustaining Membership
Emerging Professionals
University Program
Member Directory
Section Directory
Section Resources
Volunteer Opportunities
Philanthropic Donations
Events
Information
Events Calendar
Sponsorship
IES Progress Report
Featured Events
Light + Justice Symposium
IES24 Conference
Street & Area Lighting Conference
Research Symposium
Special Events
Light for Life®: Museum Symposium
Illumination Awards & Gala
Lighting Education Tour
Aviation Lighting Conference
Research & Education
Research
About IES Research
Publications
FIRES Forum
Past Projects
IES Lighting Ready Reference App
Education
eLearning Portal
Upcoming Webinars
Request IES CEU/AIA-LUs
LC Study Group
Register Now for Our Next Webinar
Standards
Standards
Purchase Standards
Browse Standards
Nomenclature & Definitions
Standards Errata & Addenda
Information
What’s New
Standards Process
Standards in Public Review
Toolbox
IES Standards Toolbox
My Lighting Library
My Illuminance Selector
My Reference Retriever
LD+A
Store
Donate
Join
My IES
overcast sky
[10.5.5.1.4] A sky that has 100% cloud cover; the sun is not visible.
« Back to Definitions Index
