Those are normal
trade winds conditions (except for the seas, which I assume are left over from a cold front). What to expect:
Just like everywhere else "fetch" is one determinant of wave height. If you are anchored in the lee of the barrier reef, like on the sand flats at Tobacco Caye, then fetch is maybe 20 yards so seas are zilch. Cool spot to
anchor with seas breaking on the reef just in front of you and you are anchored in a 6' deep crystal clear pool with zero wave action, but you still get the full force of the
wind.
Almost all other
anchorages in
Belize have good protection in these conditions too.
Underway in open
water between the reef and the inner channel you can expect a light to moderate chop...perfect sailing conditions...a good breeze and minimal wave action. An iconic
route to appreciate this is sailing from Tobacco Caye to Southwater Caye...obstruction free waters just inside the barrier reef...an off the
wind sail in a beautiful area, in calm
water with full unobstucted
trade winds, just inside the barrier reef with waves crashing on it...awesome.
In the Inner Channel, a natural area of wide deep water which runs between the mainland and the cayes from near
Belize City all the way to Guatemalan waters, fetch distance is much greater. Especially if winds are a bit more northerly. So it can get a bit bumpy with seas of a couple of feet, some a bit higher. This affect is enhanced by the afternoon sea breeze...so it gets rougher in the afternoon.
Ideally dont plan to
head N in the Inner Channel in the afternoon...do that in the early AM...ideally while the land breeze effect is still active, but at least before the sea breeze effect kicks in.
The biggest seas you are likely to see in those conditions inside the reef are about 3'...and that would be in a very exposed area of the Inner Channel...like S of Monkey River Town near Punta Negra...an area that due to its hyrography tends to get rough.