Imput a date without getting a nan

Sorry this is really basic, I'm trying to plot wave height data from a buoy over a year and can't figure out how to input the date without getting NaN?

Answer 1

[the cyclist]

DateStrings = {'2021-05-26';'2021-08-03'};
t = datetime(DateStrings,'InputFormat','yyyy-MM-dd');
waveHeight = [2 3];
figure
plot(t,waveHeight)

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