In recent years, climate change has negatively affected open field tomato production. Extremely high temperatures and changes in moisture conditions lead to an increase in the proportion of below the quality standard production and to economic losses. Despite these concerns, the impact of climate change on the three main production directions open field tomato cultivation in southern and central Bulgaria has not been well studied. This study aims to analyses the effects of unfavorable weather conditions on the early and total (standard and non-standard) yield of tomatoes under three fertilization options. The quantity and ratio of yields were studied for three different periods of planting on polyethene mulch in the Plovdiv region during the period 2019-2021. Mineral and organic fertilizations resulted in higher early and total yields compared to unfertilized plants. The tomatoes fertilized with Arcobaleno had a total yield 9% lower compared to NPK. The reported yield below the quality standard in early harvest was highest in the control (37.0%) and lowest (27.8%) in mineral fertilization during the first planting period. The days with an adverse effect on tomatoes during the study period were between 31 and 38, about 30% of their growing season. The results also show that fertilization mitigates the impact of adverse weather conditions and increases the ratio of standard to quality fruits in favor of the standard ones. The correlation between weather indices and yield weakens significantly with mineral fertilization. During the three years of the study, the best results were reported for the first, earliest planting date.