  We study three astrophysical/cosmological consequences of nonminimal
couplings to gravity in wavelike vector dark matter. In the nonrelativistic
limit, the nonminimal coupling with the lowest mass dimension leads to
effective self-interactions that affect the mass-radius relation of vector
solitons, growth of linear perturbations during structure formation, and the
speed of gravitational waves (GWs). Based on the success of cold dark matter on
large-scale perturbations and the current limits on GW speed, we constrain the
dark matter mass and nonminimal coupling strength to be within the range
$|\xi_1| / m^2 \ll 10^{50} \mathrm{eV^{-2}}$ and $-3\times 10^{46}
\mathrm{eV^{-2}} \lesssim \xi_2 / m^2 \lesssim 8 \times 10^{48}
\mathrm{eV^{-2}}$.
