The holdover time (HOT) guidelines provide estimates of how long aircraft anti-icing fluids will be effective. They help aircraft flight crews make decisions when de-icing and anti-icing an aircraft on the ground.
On this page
- Current HOT guidelines
- Current degree-specific holdover time (DSHOT) database
- About the HOT guidelines
- Archived HOT guidelines
- Regression information documents
- Contact us
- Related links
Current HOT guidelines
Request a Copy of the Winter 2026-2027 Holdover Time (HOT) Guidelines: Original issue, August 11, 2026
To receive the guidelines, you will have to provide a valid e-mail address when prompted.
HOT Guidelines: Original issue, August 11, 2026 Request a copy of the Winter 2026-2027 Holdover Time (HOT) Guidelines: Original issue, August 11, 2026
About the HOT guidelines
We update and reissue HOT guidelines every year. Sometimes we publish a revision in the same year.
These guidelines contain tables with explanatory notes. These tables provide aircraft flight crews with safe holdover times given the following criteria:
- Air temperature
- Type of precipitation
- Rate of precipitation
- Type of de-icing or anti-icing fluid
Normally, aircraft should not take off after the holdover time has expired. Aircraft may take off only after either:
- a pre-take-off contamination inspection is done
- the aircraft is de-iced or anti-iced again
Refer to the Guidelines for Aircraft Ground-Icing Operations (TP 14052) when using the HOT guidelines.
Archived HOT guidelines
The following guidelines are no longer used. We provide them for informational purposes only. If you require an alternative format, please contact us.
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2025-2026
Request a copy of archived HOT guidelines—Original issue, August 2025
To receive the archived HOT guidelines, you will have to provide a valid e-mail address when prompted.
Archived HOT guidelines—Original issue, August 2025 Request a copy of archived HOT guidelines—Original issue, August 2025
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2024-2025
Request a copy of archived HOT guidelines—Original issue, August 2024
To receive the archived HOT guidelines, you will have to provide a valid e-mail address when prompted.
Archived HOT guidelines—Original issue, August 2024 Request a copy of archived HOT guidelines—Original issue, August 2024
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2023-2024
Request a copy of archived HOT guidelines—Original issue, August 2023
To receive the archived HOT guidelines, you will have to provide a valid e-mail address when prompted.
Archived HOT guidelines—Original issue, August 2023 Request a copy of archived HOT guidelines—Original issue, August 2023
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2022-2023
Request a copy of archived HOT guidelines—Revision 2.0, August 2022
To receive the archived HOT guidelines, you will have to provide a valid e-mail address when prompted.
Archived HOT guidelines—Revision 2.0, August 2022 Request a copy of archived HOT guidelines—Revision 2.0, August 2022
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2021-2022
Request a copy of archived HOT guidelines—Original issue, August 4, 2021
To receive the archived HOT guidelines, you will have to provide a valid e-mail address when prompted.
Archived HOT guidelines—Original issue, August 4, 2021 Request a copy of archived HOT guidelines—Original issue, August 4, 2021
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2020-2021
Request a copy of archived HOT guidelines—Original issue, August 2020
To receive the archived HOT guidelines, you will have to provide a valid e-mail address when prompted.
Archived HOT guidelines—Original issue, August 2020 Request a copy of archived HOT guidelines—Original issue, August 2020
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2019-2020
Request a copy of archived HOT guidelines—Original issue, August 2019
To receive the archived HOT guidelines, you will have to provide a valid e-mail address when prompted.
Archived HOT guidelines—Original issue, August 2019 Request a copy of archived HOT guidelines—Original issue, August 2019
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2018-2019
Request a copy of archived HOT guidelines—Original issue, August 2018
To receive the archived HOT guidelines, you will have to provide a valid e-mail address when prompted.
Archived HOT guidelines—Original issue, August 2018 Request a copy of archived HOT guidelines—Original issue, August 2018
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2017-2018
Request a copy of archived HOT guidelines—Revision 1.0, October 2017
To receive the archived HOT guidelines, you will have to provide a valid e-mail address when prompted.
Archived HOT guidelines—Revision 1.0, October 2017 Request a copy of archived HOT guidelines—Revision 1.0, October 2017
Request a copy of archived HOT guidelines—Original issue, August 2017
To receive the archived HOT guidelines, you will have to provide a valid e-mail address when prompted.
Archived HOT guidelines—Original issue, August 2017 Request a copy of archived HOT guidelines—Original issue, August 2017
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2016-2017
Request a copy of archived HOT guidelines—Original issue, August 2016
To receive the archived HOT guidelines, you will have to provide a valid e-mail address when prompted.
Archived HOT guidelines—Original issue, August 2016 Request a copy of archived HOT guidelines—Original issue, August 2016
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2015-2016
Request a copy of archived HOT guidelines—Revision 1.0, December 2015
To receive the archived HOT guidelines, you will have to provide a valid e-mail address when prompted.
Archived HOT guidelines—Revision 1.0, December 2015 Request a copy of archived HOT guidelines—Revision 1.0, December 2015
Request a copy of archived HOT guidelines—Original issue, July 2015
To receive the archived HOT guidelines, you will have to provide a valid e-mail address when prompted.
Archived HOT guidelines—Original issue, July 2015 Request a copy of archived HOT guidelines—Original issue, July 2015
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2014-2015
Request a copy of archived HOT guidelines—Revision 1.0, August 2014
To receive the archived HOT guidelines, you will have to provide a valid e-mail address when prompted.
Archived HOT guidelines—Revision 1.0, August 2014 Request a copy of archived HOT guidelines—Revision 1.0, August 2014
Request a copy of archived HOT guidelines—Original issue, August 2014
To receive the archived HOT guidelines, you will have to provide a valid e-mail address when prompted.
Archived HOT guidelines—Original issue, August 2014 Request a copy of archived HOT guidelines—Original issue, August 2014
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2013-2014
Request a copy of archived HOT guidelines—Original issue, August 2013
To receive the archived HOT guidelines, you will have to provide a valid e-mail address when prompted.
Archived HOT guidelines—Original issue, August 2013 Request a copy of archived HOT guidelines—Original issue, August 2013
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Before 2013-2014
Request a copy of archived HOT guidelines before 2013-2014
To receive the archived HOT guidelines, you will have to provide a valid e-mail address when prompted.
Archived HOT guidelines—Revision 1.0, July 2012 Request a copy of archived HOT guidelines—Revision 1.0, July 2012
Archived HOT guidelines—Original issue, July 2012 Request a copy of archived HOT guidelines—Original issue, July 2012
Archived HOT guidelines—Original issue, July 2011 Request a copy of archived HOT guidelines—Original issue, July 2011
Archived HOT guidelines—Original issue, July 2010 Request a copy of archived HOT guidelines—Original issue, July 2010
Archived HOT guidelines—Original issue, July 2009 Request a copy of archived HOT guidelines—Original issue, July 2009
Archived HOT guidelines—Original issue, July 2008 Request a copy of archived HOT guidelines—Original issue, July 2008
Archived HOT guidelines—Revision 1.0, October 2007 Request a copy of archived HOT guidelines—Revision 1.0, October 2007
Archived HOT guidelines—Original Issue, July 2007 Request a copy of archived HOT guidelines—Original Issue, July 2007
Archived HOT guidelines—Original issue, July 2006 Request a copy of archived HOT guidelines—Original issue, July 2006
Archived HOT guidelines—Original issue, July 2005 Request a copy of archived HOT guidelines—Original issue, July 2005
Archived HOT guidelines—Revision 1.0, December 2004 Request a copy of archived HOT guidelines—Revision 1.0, December 2004
Archived HOT guidelines—Original issue, July 2004 Request a copy of archived HOT guidelines—Original issue, July 2004
Archived HOT guidelines—Revision 1.0, December 2003 Request a copy of archived HOT guidelines—Revision 1.0, December 2003
Archived HOT guidelines—Original issue, July 2003 Request a copy of archived HOT guidelines—Original issue, July 2003
Archived HOT guidelines—Original issue, September 2002 Request a copy of archived HOT guidelines—Original issue, September 2002
Archived HOT guidelines—Original issue, November 2001 Request a copy of archived HOT guidelines—Original issue, November 2001
Archived HOT guidelines—Original issue, October 2000 Request a copy of archived HOT guidelines—Original issue, October 2000
Archived HOT guidelines—Original issue, November 1999 Request a copy of archived HOT guidelines—Original issue, November 1999
Archived HOT guidelines—Original issue, October 1998 Request a copy of archived HOT guidelines—Original issue, October 1998
Archived HOT guidelines—Original issue, September 1997 Request a copy of archived HOT guidelines—Original issue, September 1997
Archived HOT guidelines—Original issue, September 1996 Request a copy of archived HOT guidelines—Original issue, September 1996
Archived HOT guidelines—Original issue, July 1995 Request a copy of the
Archived HOT guidelines—Original issue, October 1994 Request a copy of archived HOT guidelines—Original issue, July 1995
Archived HOT guidelines—Original issue, October 1993 Request a copy of archived HOT guidelines—Original issue, October 1993
Archived HOT guidelines—Original issue, November 1992 Request a copy of archived HOT guidelines—Original issue, November 1992
Archived HOT guidelines—Original issue, November 1991 Request a copy of archived HOT guidelines—Original issue, November 1991
Archived HOT guidelines—Original issue, September 1990 Request a copy of archived HOT guidelines—Original issue, September 1990
Regression information documents
To calculate more precise holdover times than those presented in the HOT guidelines, several companies manufacture and use HOT determination systems (HOTDS) to measure real-time temperature, precipitation type and precipitation rate. HOTDS use:
- weather data they collect
- regression information we provide
Request a Copy of the Winter 2026-2027 Holdover Time (HOT) Regression Information Document: August 11, 2026
To receive the guidelines, you will have to provide a valid e-mail address when prompted.
HOT Regression Information Document Request a copy of the Winter 2026-2027 Holdover Time (HOT) Regression Information Document: August 11, 2026
Contact us
Related links
- Guidelines for Aircraft Ground-Icing Operations (TP 14052)
- Aircraft icing training courses and resources (at NASA)
- When in Doubt ... Small and Large Aircraft - Aircraft Critical Surface Contamination Training for Aircrew and Groundcrew (TP 10643)
- Advisory Circular (AC) 700-030 Electronic Holdover Time (eHOT) Applications
- Advisory Circular (AC) 700-061 Degree-Specific Holdover Degree-Specific Holdover Times
- Advisory Circular (AC) 602-001 Operational Use of Remote On-Ground Ice Detection Systems (ROGIDS) for Post De-icing Applications