The consequences of the hypothesis of Lindzen (1978) that latent heat release may be a significant excitation mechanism for the semidiurnal atmospheric tide are examined in some detail. Harmonic analysis of hourly rainfall data from 79 tropical stations shows that the semidiurnal variation of rainfall in the tropics is ∼1 mm day−1 and has a phase near 0300 LST, just as Lindzen's theory requires. Analysis of data at 85 midlatitude stations shows that the sermidiurnal rainfall oscillation there has its phase rather later (about 0600). The results of simple classical tidal theory calculations which indicate that the geographical distribution of the surface pressure response to latent heat forcing largely follows that of the forcing itself are presented. This result is then used to suggest a plausible explanation for the observed seasonal cycle of the semidiurnal pressure oscillation in midlatitudes. Further calculations show that the magnitude of the non-migrating components of the semidiurnal barom... Abstract The consequences of the hypothesis of Lindzen (1978) that latent heat release may be a significant excitation mechanism for the semidiurnal atmospheric tide are examined in some detail. Harmonic analysis of hourly rainfall data from 79 tropical stations shows that the semidiurnal variation of rainfall in the tropics is ∼1 mm day−1 and has a phase near 0300 LST, just as Lindzen's theory requires. Analysis of data at 85 midlatitude stations shows that the sermidiurnal rainfall oscillation there has its phase rather later (about 0600). The results of simple classical tidal theory calculations which indicate that the geographical distribution of the surface pressure response to latent heat forcing largely follows that of the forcing itself are presented. This result is then used to suggest a plausible explanation for the observed seasonal cycle of the semidiurnal pressure oscillation in midlatitudes. Further calculations show that the magnitude of the non-migrating components of the semidiurnal barom...