October weather forecast
Castanhal, Brazil

October, like September, is another hot spring month in Castanhal, Brazil, with temperature in the range of an average low of 22.4°C (72.3°F) and an average high of 33.5°C (92.3°F).

Temperature

During October and November, Castanhal registers its highest temperatures, averaging a high of 33.5°C (92.3°F).

Heat index

Throughout October, the heat index is calculated to be a life-threatening hot 49°C (120.2°F). Be alert: Heat exhaustion along with heat cramps are probable. Heatstroke is a threat with sustained physical activity.
It is important to note that the heat index values are for shaded areas and light wind scenarios. The direct sunshine could escalate the heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'felt air temperature', is a value derived by merging air temperature with the humidity to convey how the climate feels. A person's impression of weather can be shaped by many aspects, among them metabolic variations, pregnancy, and levels of physical activity. The sun, when shining directly, can have a significant impact on the perceived temperature, increasing the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are essentially critical for children. Kids are usually more vulnerable than adults, given their lesser sweating ability. Along with their larger skin surface relative to their small stature and the excess heat due to their activity, their risk is amplified.
One way the human body deals with excessive warmth is by perspiring and allowing sweat to evaporate. Under high air temperature and high humidity (high heat index) conditions, the body's ability to perspire is compromised, increasing the sensation of heat. If heat absorption exceeds the body's cooling ability, body temperature can elevate, resulting in potential thermal illnesses.

Humidity

In Castanhal, the average relative humidity in October is 77%.

Rainfall

In October, the rain falls for 24 days. Throughout October, 58mm (2.28") of precipitation is accumulated. In Castanhal, Brazil, during the entire year, the rain falls for 332.9 days and collects up to 1589mm (62.56") of precipitation.

Daylight

In Castanhal, the average length of the day in October is 12h and 8min.
On the first day of the month, sunrise is at 05:57 and sunset at 18:04. On the last day of October, in Castanhal, sunrise is at 05:50 and sunset at 18:00 -03.

Sunshine

In October, the average sunshine in Castanhal is 8h.

UV index

The months with the highest UV index in Castanhal are May, July, September through November, with an average maximum UV index of 7. A UV Index estimate of 6 to 7 represents a high health hazard from exposure to the Sun's UV rays for ordinary individuals.
Note: The UV index of 7 during October leads to these advisories:
Take precautions and adopt sun safety practices. Protection against sunburn is obliged. Avoid direct Sun exposure and seek shade from 10 a.m. to 4 p.m., the period of highest UV radiation. Remember, however, that not all shade structures offer full protection. For excellent sun protection for the eyes, ears, face, and neck, consider a wide-brim hat.