Climate Overview
The climate in Castelo do Piauí is hot. The average annual temperature is 29°C and approximately 916mm of precipitation falls per year. March is the wettest month, receiving around 288mm of rainfall. Castelo do Piauí sits near the equator, so seasonal temperature differences are minimal throughout the year.
Temperature
Castelo do Piauí sees moderate temperature variation throughout the year, ranging from 23°C to 38°C. October is the hottest month, with daytime highs reaching 38°C and an average of 32°C. July is the coolest month, with minimum temperatures around 23°C and an average of 29°C. On average, daily temperatures fluctuate by about 10°C between overnight lows and afternoon highs.
Precipitation
Castelo do Piauí is a moderately rainy area, receiving approximately 916mm of precipitation annually, which averages out to around 76mm per month. The wettest month is March, averaging 288mm of rainfall. February and April also tend to see above-average precipitation. The driest month is August, with just 0mm. That's 287mm less than March, the wettest month. Rainfall is heavily concentrated in certain months, creating a distinct wet and dry season. Visitors should plan around these patterns, as the difference between peak and low months is dramatic.
Wind
Castelo do Piauí is mildly breezy, with an average annual wind speed of 16km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is September, averaging 21km/h, noticeable enough to affect lighter outdoor activities. The calmest conditions occur in March, with average winds dropping to 11km/h, making it an ideal period for wind-sensitive activities. There is moderate seasonal variation in wind speed, with a 10km/h gap between the calmest and windiest months. Wind tends to be stronger during winter months, driven by seasonal pressure systems. The seasonal averages break down to 19km/h in winter, 19km/h in spring, 14km/h in summer, 13km/h in autumn.
Seasons
89 days until Winter
It is currently autumn in Castelo do Piauí, which began on March 20, 2026. Castelo do Piauí sits near the equator, so the traditional four-season cycle is less pronounced — temperatures remain relatively stable year-round. The warmest period peaks in October at around 38°C, while the coldest stretch bottoms out in July near 23°C. Winter is next, beginning on June 21, 2026 — 89 days from now.
Spring
Temperatures range from 25 to 38°C. Precipitation is minimal, with only around 25mm for the entire season. Winds are moderate at around 19km/h. Light layers work well as temperatures warm through the season — a great time to be outdoors.
Summer
Temperatures range from 24 to 36°C. Rainfall is heavy, totalling around 394mm across the season with a monthly average of 131mm. Winds are generally light, averaging 14km/h. Light, breathable clothing is ideal — perfect conditions for outdoor activities.
Autumn
Temperatures range from 24 to 33°C. Rainfall is heavy, totalling around 483mm across the season with a monthly average of 161mm. Winds are generally light, averaging 13km/h. A waterproof jacket and sturdy footwear are recommended as rain becomes more frequent.
Winter
Temperatures range from 23 to 36°C. Precipitation is minimal, with only around 14mm for the entire season. Winds are moderate at around 19km/h. A light jacket or sweater is usually sufficient, though cooler evenings may call for an extra layer.
Monthly Climate Data
The table below shows monthly climate averages for Castelo do Piauí based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.
