  An analysis of experimental heat capacity at $T>T_{c}$ is presented for
series of samples $(R)Ba_2Cu_3O_{6+x}$ (with $x$ close to optimal). For all
samples the anomaly was discovered which occurred steadily in the interval
250-290 K (anomaly $T_{h}$). The anomaly $T_{h}$ looks like a phase transition
anomaly. It was shown that the anomaly $T_{h}$ correlates with superconducting
anomaly $T_c$, temperatures $T_{h}$ and $T_{c}$ being connected by the ratio
$T_{h}\approx 3T_c$. The anomaly $T_{h}$ is interpreted as the origination of
pairing the charge carriers. Anomalies at $T\approx 3T_c$ were also detected in
heat capacity of low temperature superconductors $Hg$ and $Nb_3Ge$.
