The weather becomes a mixed bag as
April approaches. The temperature range remains static from 22.6°C (72.7°F) to 30.1°C (86.2°F) compared to
March and something more distinct is noticeable. Despite the constant rainfall from the preceding month, the overall precipitation count lowers slightly. However, it's not all cloudy skies and dreariness, as the month actually sees the length of sunny periods remaining consistent with the earlier months.
Temperature
The commencement of April records an average high-temperature of a still tropical 30.1°C (86.2°F), barely varying from March's 30.2°C (86.4°F). Nighttime temperatures hover around an average low of 22.6°C (72.7°F) in April.
Heat index
For April, the heat index is calculated to be a fiery hot 39°C (102.2°F). Take extra safety measures to prevent heat exhaustion and heat cramps. Heatstroke could follow lengthy activity.
Know that the heat index computations account for shaded terrains and slight winds. The heat index values could be amplified by up to 15 Fahrenheit (8 Celsius) degrees in direct sunlight.
Note: The heat index, also known as 'feels like' or 'apparent temperature', quantifies the warmth felt when relative humidity is considered. Elements such as metabolic variations, pregnancy, and physical exertion can influence one's weather perception. When in direct sunlight, one should be cautious as it can raise the heat index by as much as 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for babies and toddlers. Children often do not understand the need to rest and hydrate. Thirst is a late manifestation of dehydration - therefore, it is essential to stay hydrated, particularly during prolonged physical activities.
The human body has a built-in cooling mechanism through perspiration; evaporating sweat dissipates the excess heat. An upsurge in relative humidity affects normal body cooling mechanisms by slowing evaporation, hence reducing the rate at which the body cools and intensifying the perception of heat. When heat gain surpasses the level the body can shed, body temperature begins to increase, and consequently, overheating and dehydration can occur, with varying severity.
Humidity
In
São Tomé, the average relative humidity in April is 83%.
Rainfall
In São Tomé, during April, the rain falls for 11 days and regularly aggregates up to 122mm (4.8") of precipitation. Throughout the year, there are 94 rainfall days, and 885mm (34.84") of precipitation is accumulated.
Sea temperature
February through April, with an average sea temperature of 29°C (84.2°F), are months with the warmest seawater in São Tomé,
São Tomé and Príncipe.
Note: Water temperatures between 25°C (77°F) and 29°C (84.2°F) are ideal for all water activities, offering enjoyment without causing discomfort over extended periods.
Daylight
In April, the average length of the day is 12h and 7min.
On the first day of the month, sunrise is at 05:33 and sunset at 17:40. On the last day of April, sunrise is at 05:26 and sunset at 17:34 GMT.
Sunshine
In April, the average sunshine in São Tomé, São Tomé and Príncipe, is 4.2h.
UV index
The months with the highest UV index are
January through
May,
August through
December, with an average maximum UV index of 12. A UV Index estimate of 11, and higher, represents an extreme threat to health from exposure to the Sun's UV rays for average individuals.
Note: In April, a daily maximum UV index of 12 leads to the following instructions:
Enforce every key safety measure. Those with light skin might get burns in a matter of minutes. The Sun's UV radiation is most powerful between 10 a.m. and 4 p.m. To the extent possible, limit exposure to the direct sun during these hours. For a sun-safe wardrobe, go for clothes that are tightly woven and generously sized. Broad-spectrum sunscreen with an SPF of 30 or above should be applied generously and reapplied every two hours and right after any outdoor activity or swim. Be vigilant! The Sun's UV rays get a boost from sand and water reflections.