The weather is getting warmer.

1. The mercury column in the thermometer expands when heated-"The outside temperature rises-"Spring has come.

Melting snow-rising outdoor temperature-spring is coming.

3. The sunshine time increases-"The direct point of the sun begins to move northward-"Spring is coming.

4. The static electricity generated by the body is reduced-"The air changes from dry to moist"-spring is coming.