\begin{table}%t2
\caption{Median wind speeds in m/s at Dome C over the course of
several years (see text).}\label{tab2}
%\centering
\par
\begin{tabular}{cccc}
\hline \hline
Year & All data & Winter & Astronomical darkness \\
\hline
1984 & 2.4 & 2.1 & 1.9 \\
1990 & 2.9 & 2.9 & 2.9 \\
1996 & 3.0 & 3.0 & 3.0 \\
2002 & 2.5 & 2.5 & 2.2 \\
2003 & 2.8 & 2.8 & 2.5 \\
 \hline
\end{tabular}
\end{table}