Do not charge the watch at high temperature (about 60°C/140 °F or higher).
Charging in excessive high temperature may cause deformation and/or discoloration of the dial or solar cell or malfunction of mechanical parts.

Take special care when charging the watch in a place like those below:
・Under lamps emitting excessive heat such as an incandescent lamp or a halogen lamp. Take enough distance (50 cm or more) when charging.
・On the dashboard of a vehicle. It can get extremely hot even in seasons other than summer.