Do you need to know, when is the best time to go to Sao Tome and Principe? Then you should take a look here, what weather you can expect there during the year.
The climate of Sao Tome and Principe is tropical. You can generally expect hot and humid weather. Rainy season is from October to May. There are only little seasonal variation of temperature.
When speaking about the usual weather in this state, the information is relevant for example for these popular places: Sao Tome and Principe.
Let's look now what weather you can expect here. (Warning: As we don't have reliable data for this country, we use data from nearby locations for these statistics.) The warmest month here is March, the average maximum temperature is 31 ℃ (87.8 ℉). The average minimum temperature in this month is 23.8 ℃ (74.84 ℉). The coldest month here is July, the average maximum temperature is 26 ℃ (78.8 ℉). The average minimum temperature in this month is 22.6 ℃ (72.68 ℉). 
When travelling to some places in Sao Tome and Principe, always consider the altitude of the the place as well. The highest point here is Pico de Sao Tome (2024 m) and the lowest point is Atlantic Ocean (0 m). So there are quite big differences in altitudes in this country, so you can expect the weather to be different in different altitudes as well. Keep in mind, that the temperature usually decreases by 1.2 - 1.9 ℃ (2.2 - 3.5 ℉) per 200 m (656 ft), depending on the other conditions. (And we should add, that in the very special condition named thermal inversion even the temperature may be higher in higher altitudes.)
Typical (usual) weather in Sao Tome and Principe in January is this: The average highest temperature in Sao Tome and Principe in January is 29.7 ℃ (85.46 ℉). The average lowest temperature is 24.3 ℃ (75.74 ℉). At the beginning of January you can expect lower temperatures, the average highest temperature is around 29.55 ℃ (85.19 ℉). At the end of January you can expect higher temperatures, the average highest temperature is around 30.1 ℃ (86.18 ℉). The average rainfall is 247.2 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:05 (hours and minutes), in the middle of the month 12:05 and at the end of the month 12:05.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Sao Tome and Principe in February is this: The average highest temperature in Sao Tome and Principe in February is 30.5 ℃ (86.9 ℉). The average lowest temperature is 23.8 ℃ (74.84 ℉). At the beginning of February you can expect lower temperatures, the average highest temperature is around 30.1 ℃ (86.18 ℉). At the end of February you can expect higher temperatures, the average highest temperature is around 30.75 ℃ (87.35 ℉). The average rainfall is 244.4 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:05 (hours and minutes), in the middle of the month 12:06 and at the end of the month 12:06.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Sao Tome and Principe in March is this: The average highest temperature in Sao Tome and Principe in March is 31 ℃ (87.8 ℉). The average lowest temperature is 23.8 ℃ (74.84 ℉). At the beginning of March you can expect lower temperatures, the average highest temperature is around 30.75 ℃ (87.35 ℉). At the end of March you can expect lower temperatures, the average highest temperature is around 30.6 ℃ (87.08 ℉). The average rainfall is 359.7 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:06 (hours and minutes), in the middle of the month 12:06 and at the end of the month 12:06.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Sao Tome and Principe in April is this: The average highest temperature in Sao Tome and Principe in April is 30.2 ℃ (86.36 ℉). The average lowest temperature is 23.1 ℃ (73.58 ℉). At the beginning of April you can expect higher temperatures, the average highest temperature is around 30.6 ℃ (87.08 ℉). At the end of April you can expect higher temperatures, the average highest temperature is around 30.25 ℃ (86.45 ℉). The average rainfall is 335.9 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:06 (hours and minutes), in the middle of the month 12:07 and at the end of the month 12:07.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Sao Tome and Principe in May is this: The average highest temperature in Sao Tome and Principe in May is 30.3 ℃ (86.54 ℉). The average lowest temperature is 24 ℃ (75.2 ℉). At the beginning of May you can expect lower temperatures, the average highest temperature is around 30.25 ℃ (86.45 ℉). At the end of May you can expect lower temperatures, the average highest temperature is around 28.9 ℃ (84.02 ℉). The average rainfall is 251.4 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:07 (hours and minutes), in the middle of the month 12:08 and at the end of the month 12:08.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.
Typical (usual) weather in Sao Tome and Principe in June is this: The average highest temperature in Sao Tome and Principe in June is 27.5 ℃ (81.5 ℉). The average lowest temperature is 23.6 ℃ (74.48 ℉). At the beginning of June you can expect higher temperatures, the average highest temperature is around 28.9 ℃ (84.02 ℉). At the end of June you can expect lower temperatures, the average highest temperature is around 26.75 ℃ (80.15 ℉). The average rainfall is 54.9 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:08 (hours and minutes), in the middle of the month 12:08 and at the end of the month 12:08.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Sao Tome and Principe in July is this: The average highest temperature in Sao Tome and Principe in July is 26 ℃ (78.8 ℉). The average lowest temperature is 22.6 ℃ (72.68 ℉). At the beginning of July you can expect higher temperatures, the average highest temperature is around 26.75 ℃ (80.15 ℉). At the end of July you can expect higher temperatures, the average highest temperature is around 26.45 ℃ (79.61 ℉). The average rainfall is 6.7 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:08 (hours and minutes), in the middle of the month 12:08 and at the end of the month 12:08.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Sao Tome and Principe in August is this: The average highest temperature in Sao Tome and Principe in August is 26.9 ℃ (80.42 ℉). The average lowest temperature is 22.5 ℃ (72.5 ℉). At the beginning of August you can expect lower temperatures, the average highest temperature is around 26.45 ℃ (79.61 ℉). At the end of August you can expect higher temperatures, the average highest temperature is around 27 ℃ (80.6 ℉). The average rainfall is 13.5 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:08 (hours and minutes), in the middle of the month 12:07 and at the end of the month 12:07.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Sao Tome and Principe in September is this: The average highest temperature in Sao Tome and Principe in September is 27.1 ℃ (80.78 ℉). The average lowest temperature is 23.4 ℃ (74.12 ℉). At the beginning of September you can expect lower temperatures, the average highest temperature is around 27 ℃ (80.6 ℉). At the end of September you can expect higher temperatures, the average highest temperature is around 27.75 ℃ (81.95 ℉). The average rainfall is 103.7 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:07 (hours and minutes), in the middle of the month 12:06 and at the end of the month 12:06.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Sao Tome and Principe in October is this: The average highest temperature in Sao Tome and Principe in October is 28.4 ℃ (83.12 ℉). The average lowest temperature is 23.6 ℃ (74.48 ℉). At the beginning of October you can expect lower temperatures, the average highest temperature is around 27.75 ℃ (81.95 ℉). At the end of October you can expect higher temperatures, the average highest temperature is around 28.6 ℃ (83.48 ℉). The average rainfall is 434.7 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:06 (hours and minutes), in the middle of the month 12:06 and at the end of the month 12:06.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Sao Tome and Principe in November is this: The average highest temperature in Sao Tome and Principe in November is 28.8 ℃ (83.84 ℉). The average lowest temperature is 23.8 ℃ (74.84 ℉). At the beginning of November you can expect lower temperatures, the average highest temperature is around 28.6 ℃ (83.48 ℉). At the end of November you can expect higher temperatures, the average highest temperature is around 29.1 ℃ (84.38 ℉). The average rainfall is 502.3 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:06 (hours and minutes), in the middle of the month 12:05 and at the end of the month 12:05.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.Typical (usual) weather in Sao Tome and Principe in December is this: The average highest temperature in Sao Tome and Principe in December is 29.4 ℃ (84.92 ℉). The average lowest temperature is 23.7 ℃ (74.66 ℉). At the beginning of December you can expect lower temperatures, the average highest temperature is around 29.1 ℃ (84.38 ℉). At the end of December you can expect higher temperatures, the average highest temperature is around 29.55 ℃ (85.19 ℉). The average rainfall is 300 mm (look here, what this number means). When planning your travel, please, keep in mind, that actual weather may differ from these average values. The length of the day at the beginning of this month is approximately 12:05 (hours and minutes), in the middle of the month 12:05 and at the end of the month 12:05.This data is approximate because we do not have exact data for this country. It is important to say, that the weather may differ significantly in different altitudes, especially in mountains.