Safety

Reading Wind, Waves and Small Craft Advisories

by Akayak Editors

You pull up the marine forecast and see a Small Craft Advisory. The National Weather Service’s Marine Forecasts FAQ describes an alert with criteria that depend on the region, rather than one national wind-and-wave threshold.1

This page summarizes published safety guidance. It is not a substitute for instruction, and conditions on your water may differ. Check the current rules for the state and water you paddle.

Key Takeaways

  • Advisory criteria concern wind, seas and sometimes ice. The National Weather Service also names operator experience and the vessel’s type, size and seaworthiness as considerations.1
  • A Paddler’s Guide to Safety, published by the U.S. Coast Guard Auxiliary with the American Canoe Association (ACA) in 2023, asks you to check marine and local lake forecasts before heading out; afternoon conditions may differ from the morning (p. 30).2
  • The National Weather Service’s lightning guidance says to move immediately to safe shelter when you hear thunder and stay there at least 30 minutes after the last thunder.3
  • The ACA’s Smart Start Chapter 1 asks you to dress for the water temperature, not just the air temperature (p. 27; PDF metadata May 12, 2026).4

What a Small Craft Advisory Means for Mariners

The National Weather Service’s undated Marine Forecasts FAQ says there is no precise definition of a small craft: any vessel adversely affected by the criteria should count as one. It also allows an advisory for hazardous sea or lake ice.1

These are criteria for issuing an advisory to small craft in general. They do not establish that lighter wind or smaller seas suit your boat or skills. For paddling guidance, the 2023 Auxiliary/ACA guide says wind may dictate a change of venue (p. 30) and to wait for better conditions if bad weather or water conditions are forecast (p. 55). The safety guides cover the wider trip-planning decisions.2

Regional Small Craft Advisory Criteria

Each region sets criteria for issuing the advisory. The table follows question 14 of the National Weather Service FAQ, accessed October 2, 2026. A knot is one nautical mile per hour; for scale, 20–33 knots is about 23–38 miles per hour (37–61 kilometers per hour). The native knot values remain below.1

RegionWind criterionSeas and relationship to wind
Eastern: Maine–South Carolina, Lake Erie and Lake OntarioSustained winds or frequent gusts of 25–33 knots; in harbors and bays the local lower threshold varies from 20–25 knots, with the range extending to 33Wind and/or seas or waves of 5–7 feet (1.5–2.1 m) and greater, area dependent
Central: Minnesota–OhioSustained winds or frequent gusts on the Great Lakes of 22–33 knots, inclusiveWind and/or seas or waves greater than 4 feet (1.2 m)
Southern: Georgia–Texas and CaribbeanSustained winds of 20–33 knotsWind and/or forecast seas of at least 7 feet (2.1 m), expected for more than two hours
Western: Washington–CaliforniaSustained winds of 21–33 knotsWind and/or waves exceeding 10 feet (3.0 m), or wave steepness exceeding local thresholds
AlaskaSustained winds or frequent gusts of 23–33 knotsA separate rough-seas advisory may use locally significant conditions based on user needs, no lower than 8 feet (2.4 m)
Pacific: Hawaii, Guam and other areas, with the exception at rightSustained winds of at least 25 knots; Guam/Northern Mariana Islands exception: 22–33 knotsGeneral criterion: wind AND seas of at least 10 feet (3.0 m). Guam/Northern Mariana Islands: wind AND/OR combined seas of at least 10 feet

The FAQ describes frequent gusts as typically lasting more than two hours. These regional numbers are not a personal paddling limit; consult the forecast for the zone covering your route.1

Reading River Flow and Tide Data

The river flow and tides guide explains how these readings relate to your route.

For river planning, the 2023 Auxiliary/ACA guide asks you to identify the appropriate U.S. Geological Survey (USGS) gauge for your river section and obtain local knowledge of the levels suitable for that section. It points to USGS gauges and American Whitewater river information, including recommended levels (p. 29).2

USGS’s Instantaneous Values service says readings are usually recorded every 15 minutes and transmitted hourly. Its WaterAlert user guide explains that recording and reporting intervals vary, transmissions can be delayed, and WaterAlert cannot use an observation until it has been transmitted. Read the observation timestamp at your selected station; a quarter-hour recording interval does not promise a new online reading every quarter hour.56

American Whitewater’s November 12, 2024 description of its gauge service identifies several gauge providers and low, medium, high, too-low and too-high flow ranges. It also asks for gauges to be added where missing and for limited or outdated flow recommendations to be edited. A river page may therefore lack a gauge or a current range. Use the linked gauge and units for that particular section, rather than assuming every reach has a current discharge-based range.7

When Thunder Roars, Get Off the Water

The National Weather Service’s JetStream Lightning Safety page says there is no safe place outside during a thunderstorm. If you hear thunder, including a distant rumble, move immediately to safe shelter: a substantial building with electricity or plumbing, or an enclosed metal-topped vehicle with its windows up. It also says not to wait for rain or first thunder when storms develop or the sky looks threatening.3

The 30-Minute Wait

Stay in safe shelter for at least 30 minutes after the last sound of thunder. The lightning and storms guide explains shelter and returning to the water. A flash-to-thunder distance calculation is not a reason to postpone shelter.3

Water Temperature and Clothing for Immersion

The National Oceanic and Atmospheric Administration’s (NOAA) National Data Buoy Center publishes water-temperature observations. Its undated Measurement Descriptions page defines WTMP as sea-surface temperature in Celsius, with measurement depth depending on the buoy or fixed platform. These are station observations, rather than a NOAA-prescribed sequence of paddling checks.8

The ACA’s Smart Start Chapter 1 asks you to consider the water temperature and how long you could be exposed after a capsize (p. 27). It places your life jacket over a wetsuit or drysuit (p. 30).4

The Older ACA Cold-Water Brochure

The older ACA-branded Cold Water Survival brochure hosted by United States Power Squadrons has no printed date; its PDF metadata records creation in 2012 and modification in 2015. Page 1 calls a wetsuit a must and a drysuit highly recommended when water is 60°F (15.6°C) or colder, OR when combined air and water temperatures are below 120°F. For that historical formula you add both readings in Fahrenheit; the sum is not a single temperature to convert to Celsius. This is historical brochure wording, rather than a numerical cutoff in Smart Start Chapter 1. The brochure’s line does not establish that warmer water is safe. The guide to where cold water starts compares the published thresholds.94

The ACA’s Smart Start Chapter 1 discusses equipment on pages 24–25. It lists a pea-less whistle attached to your life jacket, a headlamp, a phone in a waterproof pouch, first-aid supplies, water, snacks and dry clothing. It also discusses dry bags, lights and visual distress signals. For removing water from a boat, page 25 names sponges, bilge pumps or buckets.4

Federal Requirements to Check

For ordinary recreational canoes and kayaks, 33 Code of Federal Regulations (CFR) Part 175 requires a Coast Guard-approved wearable life jacket for each person, subject to its exceptions. Each required jacket must be readily accessible, serviceable and of the appropriate size and fit; follow its approval label and any manual conditions referenced there. Racing craft and sailboards have express carriage exemptions (§175.17).10

The federal under-13 wear rule applies while underway, except below decks or in an enclosed cabin; an applicable state child-wear statute replaces that federal rule on waters under the state’s jurisdiction (§§175.15(c), 175.25).10

On waters governed by the Inland Navigation Rules, a vessel under 39.4 feet (12 m) that lacks the specified sound appliances must have another means of making an efficient sound signal (Rule 33). At sunset–sunrise, a vessel under oars that does not show sailing-vessel lights must show an all-round white light or have a white torch or lantern ready to exhibit in time to prevent collision (Rules 20 and 25).11

Manually propelled boats must also carry suitable night visual distress signals between sunset and sunrise on waters covered by Part 175 Subpart C, including U.S. Great Lakes waters, territorial seas and the defined connected coastal waters. These are selected requirements, not a complete list for every route; required safety gear for paddling explains the scope and conditions.10

Footnotes

  1. https://www.weather.gov/marine/faq (National Weather Service, Marine Forecasts FAQ, question 14; undated; accessed October 2, 2026.) ↩ ↩2 ↩3 ↩4 ↩5

  2. https://edept.cgaux.org/pdf/PaddlersGuideSafety042023.pdf (U.S. Coast Guard Auxiliary with the American Canoe Association, A Paddler’s Guide to Safety, 2023; pp. 29–30, 55; accessed September 19, 2026.) ↩ ↩2 ↩3

  3. https://www.noaa.gov/jetstream/lightning/lightning-safety (National Weather Service, JetStream Lightning Safety, hosted by NOAA; page displays “Last updated June 22, 2026”; accessed October 2, 2026.) ↩ ↩2 ↩3

  4. https://americancanoe.org/wp-content/uploads/2026/05/Smart-Start-Chapter-1-Smart-Gear.pdf (American Canoe Association; PDF metadata May 12, 2026; accessed September 19, 2026.) ↩ ↩2 ↩3 ↩4

  5. https://waterservices.usgs.gov/docs/instantaneous-values/ (U.S. Geological Survey, Instantaneous Values; undated; accessed October 2, 2026.) ↩

  6. https://accounts.waterdata.usgs.gov/wateralert/user-guide/ (U.S. Geological Survey, WaterAlert user guide, data recording/transmission and subscription hints; undated; accessed October 2, 2026.) ↩

  7. https://www.americanwhitewater.org/article/vutwkeg4mbnfpvdfqbea5/ (American Whitewater, new stream gauge service, November 12, 2024; accessed October 2, 2026.) ↩

  8. https://www.ndbc.noaa.gov/measdes.shtml (NOAA National Data Buoy Center, Measurement Descriptions; undated; accessed October 2, 2026.) ↩

  9. https://www.usps.org/eddept/files/cold_water_survival_aca.pdf (ACA-branded Cold Water Survival brochure; no printed date; PDF metadata created March 20, 2012, modified February 4, 2015; accessed September 19, 2026.) ↩

  10. https://www.ecfr.gov/current/title-33/chapter-I/subchapter-S/part-175 (Coast Guard regulations, §§175.11, 175.15–175.25, 175.101–175.115; eCFR October 1, 2026 version; accessed October 2, 2026.) ↩ ↩2 ↩3

  11. https://www.ecfr.gov/current/title-33/chapter-I/subchapter-E/part-83 (Inland Navigation Rules, §§83.01, 83.20, 83.25(d)(ii), 83.33(b); eCFR October 1, 2026 version; accessed October 2, 2026.) ↩