Physiological qualities of F₁ hybrid tomato seeds affected by the growing season; maturity stage at 40, 45, 50, 60, and 70 days after cross-pollination (DAP), and storage in plastic bags at 0°C for four months were studied. The characteristics of seeds from early harvested fruits (45 DAP) that subsequently ripened at ambient temperature (28 ± 2°C) for ten days (designated as “45+ripening”), were also investigated. Higher light intensity, and a wider range of night and day temperatures and relative humidity (RH), but lower night temperature and RH, were observed in the winter season compared to the rainy season. The winter climate delayed physiological maturity of the seeds by 10 days, indicated by the highest weight of dried seed, percentage germination and germination index which occurred at 60 DAP. On the other hand, in the rainy season physiological maturity occurred at 50 DAP. The proportions of irregularly shaped seeds, abnormal seedlings and weak seedlings were independent of fruit and seed maturity, while the amount of speckled seeds significantly increased with an increase in seed development on either the mother plant or the 45+ripening. Fresh (non-stored seeds) and stored seeds of the fruits harvested at 45+ripening and at 60 DAP showed the same quality. The number of fresh ungerminated seed in the seeds of 45 and 50 DAP was markedly reduced after four months storage at 0°C.