September weather forecast
Caño Negro, Costa Rica

The first month of the autumn, September, is still a warm month in Caño Negro, Costa Rica, with an average temperature varying between 23.2°C (73.8°F) and 28.9°C (84°F).

Temperature

The commencement of September notes an average high-temperature of a still warm 28.9°C (84°F), exhibiting little difference from the previous month. September nights in Caño Negro observe an average temperature dip to a still moderately hot 23.2°C (73.8°F).

Heat index

September's average heat index is estimated at a fiery hot 35°C (95°F). Take extra precautions, as heat cramps and heat exhaustion are possible. Sustained activity may result in heatstroke.
Regarding the heat index, one should be aware it's determined by shaded settings and mild winds. Exposure to the sun directly might heighten the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'apparent temperature', offers an insight into how hot it feels when we factor in moisture content. A person's impression of weather can be swayed by numerous aspects, among them metabolic variations, pregnancy, and activity levels. Be mindful that being in direct sunlight might mean feeling hotter, with the heat index rising by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. Young people are generally more susceptible than adults because they perspire less. Furthermore, their proportionally larger skin surface to their petite bodies and the increased heat output from their actions add to the risk.
One of the main methods the human body employs to cool down is by perspiring, as this process allows sweat to evaporate and remove excess heat. When air moisture content is high, the cooling process through evaporation is not as efficient, leading to an ineffective body cooling process and a feeling of overheating. The body is at risk of dehydration and related complications when it fails to shed excessive heat.

Humidity

In September, the average relative humidity is 82%.

Rainfall

In September, in Caño Negro, the rain falls for 27.7 days. Throughout September, 193mm (7.6") of precipitation is accumulated. In Caño Negro, during the entire year, the rain falls for 218.6 days and collects up to 1456mm (57.32") of precipitation.

Daylight

The average length of the day in September in Caño Negro, Costa Rica, is 12h and 11min.
On the first day of the month, sunrise is at 05:27 and sunset at 17:46. On the last day of September, sunrise is at 05:26 and sunset at 17:28 CST.

Sunshine

The average sunshine in September in Caño Negro is 8.7h.

UV index

The months with the highest UV index in Caño Negro are January through September and December, with an average maximum UV index of 7. A UV Index estimate of 6 to 7 represents a high health hazard from unsafe exposure to UV radiation for ordinary individuals.
Note: A daily high UV index of 7 in September leads to these guidelines:
Avoid excessive sunlight. Those with lighter skin may experience burning in less than 20 minutes. Stay in the shade and limit sun exposure from 10 a.m. to 4 p.m., when UV radiation is most potent. Keep in mind that shade structures like parasols or canopies do not offer full protection. Experience reduced UV exposure by about half when donning a wide-brim hat.