September weather forecast
Porto Velho, Brazil

The first month of the spring, September, is also a sweltering month in Porto Velho, Brazil, with an average temperature varying between 36.6°C (97.9°F) and 23.1°C (73.6°F).

Temperature

September, with its high-temperature average of 36.6°C (97.9°F) and a low-temperature average of 23.1°C (73.6°F), is the warmest month.

Heat index

The average heat index in September is estimated at a life-threatening hot 50°C (122°F). Be alert: Heat exhaustion along with heat cramps are probable. Heatstroke is a threat with sustained physical activity.
Heat index specifics point out values are for conditions of shade and a slight breeze. The direct sun can potentially cause the heat index to increase by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'felt air temperature', is an amalgamation of air temperature and humidity to express the equivalent perceived temperature. One's perception of temperature can vary depending on physical activity and individual heat sensitivity, influenced by factors like wind, attire, and metabolic variations. Considering the impact of direct sunlight, it's possible for the heat index to surge by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values hold particular importance for children. Typically, children face more danger than adults as they usually perspire less. Their larger skin surface relative to their small bodies and increased heat output from their activities enhance their risk.
To cool down, the human body relies on perspiration, a process where excessive heat is eliminated as sweat evaporates. When there is abundant moisture in the air, the body's cooling through the evaporation process becomes less effective, leading to the sensation of overheating. If heat absorption exceeds the body's cooling ability, body temperature can elevate, resulting in potential thermal illnesses.

Humidity

In Porto Velho, the average relative humidity in September is 59%.

Rainfall

In September, the rain falls for 14.5 days. Throughout September, 31mm (1.22") of precipitation is accumulated. In Porto Velho, during the entire year, the rain falls for 251.1 days and collects up to 1471mm (57.91") of precipitation.

Daylight

The average length of the day in September is 12h and 4min.
On the first day of the month, sunrise is at 06:16 and sunset at 18:13. On the last day of September, sunrise is at 05:59 and sunset at 18:10 -04.

Sunshine

In Porto Velho, the average sunshine in September is 9.2h.

UV index

May through November, with an average maximum UV index of 7, are months with the highest UV index. A UV Index reading of 6 to 7 represents a high threat to health from exposure to the Sun's UV radiation for average individuals.
Note: A maximum UV index of 7 in September translates into the following recommendations:
Evade overexposure. Individuals with fair skin risk burning in under 20 minutes. Stay in the shade and avoid direct Sun exposure from 10 a.m. to 4 p.m., a time when UV radiation is at its strongest, and remember that parasols or canopies do not offer full protection. For optimum UV protection, wear sun-resistant attire complemented with a hat and quality shades.