September weather forecast
Teresina, Brazil

As Teresina moves into September, it prepares to shift back to a wetter climate. However, the rainfall volume remains low, while temperatures start to creep upward, indicating the incoming transition to the wet season. The September precipitation falls to a low 8mm (0.31"), creating the driest conditions in the yearly cycle. This month is known for its relatively clear skies and optimal visibility. In summary, September in Teresina represents the tail end of the dry season with a gradual increase in temperatures and clear skies.

Temperature

Entering September in Teresina, the average high-temperature is recorded at a still sweltering 36.4°C (97.5°F), exhibiting a minimal shift from August's 35.1°C (95.2°F). Marked by a significant drop from the daytime highs, Teresina's average low-temperature in September stands at a warm 23.1°C (73.6°F).

Heat index

The heat index value for September is calculated to be an extremely hot 43°C (109.4°F). Attention: Heat exhaustion and heat cramps are quite likely. Heatstroke becomes a risk with continued exertion.
Records show heat index calculations are tailored for shaded regions and mild winds. Direct sunlight can cause a surge in the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', is a metric representing the sensation of warmth when air temperature and moisture come together. Additional elements including metabolic differences, the level of physical activity, and attire have a role in shaping the individual's temperature perception. One should be aware that direct sunshine can amplify the perceived temperature, raising the heat index by as much as 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially vital to children. Young ones regularly neglect the requirement for rest and fluid replenishment. Thirst is a late stage of dehydration - so, it is necessary to keep hydrated, particularly during extended periods of physical exertion.
Sweat evaporation, driven by perspiration, is the method the human body uses to rid itself of excessive warmth. In circumstances of high air temperature and humidity (high heat index), the body's perspiration is restricted, heightening the feeling of warmth. Heat disorders may be on the horizon when body temperatures rise from inadequate heat management.

Humidity

The least humid month is September, with an average relative humidity of 48%.

Rainfall

The month with the least rainfall is September, when the rain falls for 5.7 days and typically collects 8mm (0.31") of precipitation.

Daylight

In September, the average length of the day in Teresina, Brazil, is 12h and 5min.
On the first day of September, sunrise is at 05:50 and sunset at 17:51. On the last day of the month, sunrise is at 05:36 and sunset at 17:45 -03.

Sunshine

September has the most sunshine of the year in Teresina, with an average of 9.7h of sunshine.

UV index

January, March through December, with an average maximum UV index of 7, are months with the highest UV index in Teresina, Brazil. A UV Index estimate of 6 to 7 represents a high health hazard from exposure to the Sun's UV radiation for the average person.
Note: A maximum daily UV index of 7 during September morphs into the following directions:
Undertake protective measures and comply with sun safety rules. Shielding against skin and eye damage is essential. Minimize exposure to direct sunlight and seek shade from 10 a.m. to 4 p.m., when UV radiation is most intense, but remember that shade structures may not offer complete protection. Loose clothes with a tight weave are optimal for safeguarding yourself against the Sun's rays.