Two people are imagined as parts of a single storm in this love poem: the speaker is lightning, and the person they love is thunder. The idea is simple but tender. Lightning and thunder come from the same moment, so the two are never really apart, even if one is seen and the other heard. "You can see me and I can hear you" sums up that connection.
The middle stanza zooms in on a quiet, specific scene: 2:46 in the morning, rain on the window, a room suddenly lit up. The speaker pictures themselves as that flash, surrounding the loved one for a brief second. Then the thunder follows, and the speaker hears it as a declaration of love.
The speaker feels devoted and certain, and a little romantic in an everyday way. The mood is calm and intimate, turning a stormy night into something comforting. The repeated closing line, with the roles gently flipped, makes the bond feel mutual.