October weather forecast
São Luís, Brazil

In October, São Luís experiences slightly increased rainfall to 8mm (0.31"), indicating a trend towards the upcoming wet season. Temperatures persist in a stable range, reflecting a mild climate. Daylight hours subtly increase to 12.2 along with a sustained UV index at 12, similar to September. October effectively forms a bridge between the ending dry season and the approaching monsoon, producing a balanced display of weather characteristics.

Temperature

During October, São Luís observes a subtle ascent to a still hot 31.2°C (88.2°F) from September's 31°C (87.8°F) in the average high-temperature. Throughout the month of October, the average temperature in São Luís dips to a warm 23.7°C (74.7°F) at night.

Heat index

During October, the heat index is appraised at a scorching 42°C (107.6°F). Adopt enhanced safety measures, heat exhaustion and heat cramps could occur. Continuous activity may induce heatstroke.
Heat index data is primarily for areas with shade and subjected to light winds. When under direct sunshine, the heat index may be elevated by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'real feel', reflects the blend of air temperature and relative humidity to give a temperature impression. The impact of weather on an individual can be subjective, affected by the person's activity and heat perception, which can vary due to elements including wind, clothing, and metabolic differences. Remember, direct sunlight exposure can heighten the heat impact and might increase the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values hold particular importance for children. Children usually face more risks than adults as their ability to sweat is less. Additionally, their larger skin surface in relation to their petite bodies and higher heat output due to their activities increases their vulnerability.
To cool down, the human body relies on perspiration, a process where excessive heat is eliminated as sweat evaporates. When the air contains significant moisture, the efficiency of the evaporation process decreases, preventing the body from cooling down effectively and creating a feeling of overheating. When body heat isn't effectively managed, risks of dehydration and overheating amplify.

Humidity

In October, the average relative humidity in São Luís, Brazil, is 81%.

Rainfall

The month with the least rainfall in São Luís is October, when the rain falls for 1 days and typically collects 8mm (0.31") of precipitation.

Sea temperature

In October, the average sea temperature in São Luís is 27.5°C (81.5°F).
Note: For swimming, diving, and various water activities, the temperatures ranging from 25°C (77°F) to 29°C (84.2°F) are seen as highly enjoyable and comfortable for extended durations without any discomfort.

Daylight

In October, the average length of the day is 12h and 10min.
On the first day of October, sunrise is at 05:42 and sunset at 17:50. On the last day of the month, sunrise is at 05:34 and sunset at 17:46 -03.

Sunshine

The average sunshine in October in São Luís is 8.1h.

UV index

January through April, September through December, with an average maximum UV index of 12, are months with the highest UV index. A UV Index estimate of 11, and higher, represents an excessive health risk from unprotected exposure to Sun's UV rays for the ordinary person.
Note: In October, the maximum UV index of 12 suggests these recommendations:
Employ all crucial safeguards, unprotected skin could burn rapidly. Limit your direct sun exposure, especially between 10 a.m. and 4 p.m., when UV radiation is strongest. Shade structures might not provide complete sun protection. Sunglasses that guard against UVA and UVB rays are pivotal in minimizing sun-induced ocular damage. A broad-spectrum sunscreen of SPF 30+ should be used liberally and reapplied every two hours or post an outdoor workout or swim. Be alert! The reflection of water and sand augments UV radiation intensity.