  The edge and bulk structure of Landau levels (LLs) in a wide channel at the $
\nu =1$ quantum Hall regime is calculated for not-too-low temperatures, $\hbar
\omega_{c} \gg k_{B}T\gg \hbar v_{g}/2\ell_{0}$, where $v_{g}$ is the group
velocity of the edge states and $\ell_{0}=\sqrt{\hbar c/|e|B}$ is the magnetic
length. Edge-states correlations essentially modify the spatial behavior of the
lowest spin-up LL, which is occupied, compared to the lowest spin-down LL,
which is empty. The influence of many-body interactions on the spatially
inhomogeneous spin-splitting between the two lowest LLs is studied within the
generalized local density approximation. Temperature effects on the enhanced
spin-splitting, the position of the Fermi level within the exchange enhanced
gap and the renormalization of edge-states group velocity by edge states
screening are considered. It is shown that the maximum activation energy $G$ in
the bulk of the channel is determined by the gap between the Fermi level and
the bottom of the spin-down LL, because the gap between the Fermi level and the
spin-up LL is much larger. For the maximum value of $G$, it is shown that the
renormalized group velocity $v_{g}\propto T$ for $T\to 0$ and, in particular,
the condition of not-too-low $T$ can be satisfied for $4.2\agt T\agt0.3$ K. In
other words, the regime of not-too-low temperatures regime can be achieved even
for rather low $T$.
