São Luís
Brazil
Long-term weather forecast
Long-term weather forecast

April weather forecast and climate
São Luís, Brazil

April, the same as March, is a moderately hot autumn month in São Luís, Brazil, with temperature in the range of an average low of 23.1°C (73.6°F) and an average high of 29.6°C (85.3°F).

Temperature

In April, the average high-temperature is relatively the same as in March - a still moderately hot 29.6°C (85.3°F). In São Luís, the average low-temperature is 23.1°C (73.6°F).

Heat index

The average heat index is appraised at a torrid 39.2°C (102.6°F). Take special precautions - heat exhaustion and heat cramps are expected. Heatstroke may occur with lengthy activity.
Take into consideration that the heat index values are calculated for shade and light wind conditions. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature', 'felt air temperature', 'feels like', or 'real feel', combines air temperature and relative humidity to represent a human perceived temperature equivalent. This effect is subjective, depending on the activity and individual's heat perception influenced by various reasons (metabolic differences, pregnancy, clothing). Bear in mind that direct sunshine exposure increases weather impact, and may raise heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.
The human body normally cools itself by perspiration. Excessive warmth is eliminated from the body by evaporation of sweat. High relative humidity reduces the evaporation rate, resulting in a lower heat removal rate from the body, causing the perception of being overheated. 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

April is the most humid month, with an average relative humidity of 90%.

Rainfall

The month with the most rainfall is April when the rain falls for 22 days and typically aggregates up to 475.9mm (18.7") of precipitation.

Sea temperature

In São Luís, Brazil, the average seawater temperature is 28.6°C (83.5°F).
Note: For swimming, diving, and other water activities, temperatures between 25°C (77°F) and 29°C (84.2°F) are perceived as very enjoyable and pleasurable for prolonged periods without feeling uncomfortable.

Daylight

In São Luís, the average length of the day in April is 12.1h.

Sunshine

In April, the average sunshine in São Luís is 3.8h.

UV index

Months with the highest UV index are January through April, September through December, with an average maximum UV index of 12. A UV Index estimate of 11, and higher, represents an ultimate health vulnerability from the exposure to the Sun's UV rays for average individuals.
Note: The daily maximum UV index of 12 in April interpret into the following advice:
Practice all-important precautions. Light skin people may get burned in less than 5 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. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. A broad-spectrum sunscreen of SPF 30+ should be liberally applied and re-applied every two hours, and immediately after an outdoor workout or a swim. Beware! The strength of the UV rays is significantly increased by the reflection of the water and sand.

What is the temperature in April in São Luís?

In São Luís, in April, the average high-temperature is 29.6°C (85.3°F), and the average low-temperature is 23.1°C (73.6°F). In April, the average heat index (a.k.a. 'apparent temperature', 'real feel'), that represents influence of the relative humidity to air temperaure, is estimated at 39.2°C (102.6°F).

What is the most humid month in São Luís?

April is the most humid month in São Luís, with an average relative humidity of 90%.

What is the average humidity in April in São Luís?

In São Luís, Brazil, the average relative humidity in April is 90%.

How much does it rain in São Luís in April?

In April, in São Luís, the rain falls for 22 days. Throughout April, 475.9mm (18.7") of precipitation is accumulated.

What is the wettest month in São Luís?

April is the month with the most rainfall in São Luís, Brazil. Rain falls for 22 days and accumulates 475.9mm (18.7") of precipitation.

What is the water temperature in April in São Luís?

In São Luís, the average seawater temperature in April is 28.6°C (83.5°F). For any water activity, surface water temperatures between 25°C (77°F) and 29°C (84.2°F) are considered as excellent and extremely pleasant for lengthened periods.

How many hours of daylight does São Luís have in April?

In April, the average length of the day in São Luís, Brazil, is 12.1h.

How many hours of sunshine does São Luís have in April?

The average sunshine in April is 3.8h.

When is the highest UV index in São Luís?

Months with the highest UV index are January through April, September through December, with an average maximum UV index of 12.

How high is the UV index in April in São Luís?

In April, the average daily maximum UV index is 12. A UV Index estimate of 11, and higher, represents an excessive health risk from unsafe exposure to the Sun's UV rays.
Average temperature in April - São Luís, Brazil
  • Average high temperature in April: 29.6°C

The warmest month (with the highest average high temperature) is November (31.4°C).
Months with the lowest average high temperature are February and March (29.4°C).

  • Average low temperature in April: 23.1°C

Months with the highest average low temperature are November and December (24°C).
The coldest month (with the lowest average low temperature) is July (22.6°C).

Average humidity in April - São Luís, Brazil
  • Average humidity in April: 90%

The month with the highest relative humidity is April (90%).
The month with the lowest relative humidity is December (71%).

Average rainfall in April - São Luís, Brazil
  • Average rainfall in April: 475.9mm

The wettest month (with the highest rainfall) is April (475.9mm).
The driest month (with the lowest rainfall) is October (7.6mm).

Average rainfall days in April - São Luís, Brazil
  • Average rainfall days in April: 22 days

The month with the highest number of rainy days is March (23 days).
Months with the lowest number of rainy days are October and November (1 days).

Average sea temperature in April - São Luís, Brazil
  • Average sea temperature in April: 28.6°C

The best month for swimming (with the highest average sea temperature) is March (28.9°C).
The coldest month (with the lowest average sea temperature) is September (27.3°C).

Average daylight in April / Average sunshine in April - São Luís, Brazil
  • Average daylight in April: 12.1h

Months with the longest days are January and December (Average daylight: 12.3h).
Months with shortest days are May, June, July and August (Average daylight: 12h).

  • Average sunshine in April: 3.8h

The month with most sunshine is August (Average sunshine: 8.4h).
The month with least sunshine is March (Average sunshine: 3.5h).

Average UV index in April - São Luís, Brazil
  • Average UV index in April: 12

Months with the highest UV index are January, February, March, April, September, October, November and December (UV index 12).
Months with the lowest UV index are June and July (UV index 10).