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

May weather forecast and climate
São Luís, Brazil

The last month of the autumn, May, is a hot month in São Luís, Brazil, with average temperature fluctuating between 23.1°C (73.6°F) and 30.1°C (86.2°F).

Temperature

In May, the average high-temperature is essentially the same as in April - a tropical 30.1°C (86.2°F). The average low-temperature, in São Luís, Brazil, is 23.1°C (73.6°F).

Heat index

In May, the average heat index is appraised at a blistering 40.8°C (105.4°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. With the exposure to direct sunlight, the heat index may be increased by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like', 'apparent temperature', 'felt air temperature', or 'real feel', is calculated by taking the relative humidity value for a specific location and factoring it into the air temperature reading. This effect is individual, with diverse people perceiving weather differently for numerous reasons (wind, differences in body mass, height, and shape, pregnancy), and activity. 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. When the relative humidity is high, the evaporation rate is reduced. The warmth is removed from the body at a lower rate, causing the body to retain more heat than it would in dry air. 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

The average relative humidity in May is 89%.

Rainfall

In São Luís, it is raining for 20 days, with typically 316.5mm (12.5") of accumulated precipitation. In São Luís, during the entire year, the rain falls for 130 days and collects up to 2290.2mm (90.2") of precipitation.

Sea temperature

In São Luís, the average seawater temperature in May is 28.7°C (83.7°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

Months with the shortest days are May through August, with an average of 12h of daylight.

Sunshine

In May, the average sunshine in São Luís is 5.2h.

UV index

The average daily maximum UV index in May is 11. A UV Index value of 11, and more, symbolizes an extreme threat to health from the exposure to the Sun's UV rays for the ordinary person.
Note: The average daily UV index of 11 transform into the following instructions:
Take all required precautions, as unprotected skin and eyes can burn in 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. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun. 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 May in São Luís?

In May, the average high-temperature is 30.1°C (86.2°F), and the average low-temperature is 23.1°C (73.6°F). In May, the average heat index (a.k.a. 'real feel', 'apparent temperature'), that factores the actual air temperature with the relative humidity, is calculated to 40.8°C (105.4°F).

What is the average humidity in May in São Luís?

In São Luís, the average relative humidity in May is 89%.

How many days does it rain in May in São Luís?

In São Luís, during May, the rain falls for 20 days and regularly aggregates up to 316.5mm (12.5") of precipitation.

What is the water temperature in May in São Luís?

In São Luís, Brazil, the average seawater temperature in May is 28.7°C (83.7°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.

What is the month with the shortest days in São Luís?

Months with the shortest days in São Luís are May through August, with an average of 12h of daylight.

What is the average length of the day in May in São Luís?

In São Luís, the average length of the day in May is 12h.

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

In São Luís, the average sunshine in May is 5.2h.

What is the UV index intensity in May in São Luís?

In May, the average daily maximum UV index is 11. A UV Index of 11, and more, symbolizes an extreme health threat from the exposure to the Sun's UV rays.
Average temperature in May - São Luís, Brazil
  • Average high temperature in May: 30.1°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 May: 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 May - São Luís, Brazil
  • Average humidity in May: 89%

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

Average rainfall in May - São Luís, Brazil
  • Average rainfall in May: 316.5mm

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 May - São Luís, Brazil
  • Average rainfall days in May: 20 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 May - São Luís, Brazil
  • Average sea temperature in May: 28.7°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 May / Average sunshine in May - São Luís, Brazil
  • Average daylight in May: 12h

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 May: 5.2h

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 May - São Luís, Brazil
  • Average UV index in May: 11

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).