What GO, CAUTION & NO-GO mean

Every spot on shouldiboat.com gets one clear verdict. Here's exactly what goes into it, what each level is telling you, and the one thing it can't know about your boat.

GO conditions look good · CAUTION boatable, small boats take care · NO-GO stay in.

It's a "right now" call, on purpose

The verdict describes conditions right now and in the next hour or two — not the whole day. This matters. A morning that's flat calm can turn into a 20-knot afternoon, and an all-day average would hide both. So a thunderstorm six hours out won't turn the current verdict red on its own; instead it shows up on the hour-by-hour timeline and in a "be back in by" time. The headline answers "should I go out now?" and the timeline answers "and when should I come back?"

What feeds the verdict

The call blends several live sources — NOAA/NWS forecasts, the forecaster-edited marine grid, live NDBC buoy readings where available, and any active marine warnings — and takes the most cautious signal among them. The main drivers:

Wind and gusts

Wind is weighted on the stronger of sustained wind and gusts, because the gust is what actually catches you. Roughly: a light breeze reads calm, the mid-teens in knots starts pushing toward CAUTION, and once wind or gusts climb into the low 20s it's NO-GO for a typical small boat.

Waves — height and period

Wave height moves the needle from manageable, to choppy, to rough, to "very rough." But height alone isn't the whole story: the verdict also looks at wave period (seconds between waves). A short-period chop — waves stacked close together — is flagged as feeling rougher than the raw number suggests, which is the Great Lakes' signature nasty ride. There's more on why in how to read a marine forecast.

Marine warnings

An active Small Craft Advisory pushes the day toward CAUTION; a Gale Warning, Storm Warning or Special Marine Warning forces NO-GO regardless of the numbers. When the NWS has posted a warning for your waters, it wins. (See Small Craft Advisory, explained.)

Thunderstorms

A real chance of thunderstorms in the current window is an automatic NO-GO — open water is no place to be caught by lightning and the vicious wind shifts that come with a storm front. A more distant storm chance becomes a "watch the timeline" note rather than a red light now.

Cold water

When a buoy reports cold water, the verdict adds a cold-shock warning even on an otherwise calm day, because a fall overboard is far more dangerous than the flat surface suggests. Read cold-water safety for why a 55°F lake is a genuine hazard.

Always shown: the reasons and the raw numbers

The verdict never asks you to trust it blindly. Every call lists the specific reasons behind it ("Waves ~3 ft — rough for small boats", "Wind/gusts ~24 kt", "Active Small Craft Advisory") and shows the underlying wind, wave, gust, period and temperature figures so you can judge for yourself. If you disagree with the call for your boat and your experience, you have everything you need to override it.

shouldiboat.com is a planning aid, not an official forecast or a navigation tool. Always check the official NWS marine forecasts and use your own judgment.