Castelo do Piauí Weather in May

NASA POWER reanalysis for the half-degree grid cell around Castelo do Piauí, 1991-2020; a grid cell is an area average and can differ from a thermometer in town by several degrees

Average highs run from 30°C on May 1 to 32°C on May 31, and lows from 21°C to 21°C. Normal precipitation for the month is 65 mm over about 12 wet days.

May day by day

The normal high and low for each date, in °C.

Normal low
Normal high
Reanalysis extreme high
Reanalysis extreme low

May at a glance

Average high: 31°C
Average low: 21°C
Precipitation: 65 mm
Reanalysis high: 38°CMay 27, 1998
Reanalysis low: 17°CMay 30, 1999
Daylight: 11 h 55 min to 11 h 50 min
Cloud cover: 54%
Humidity: 74%
Dew point: 20°C
Wind: 14.0 km/h

Every day of the month

A wet day has at least 1 mm of precipitation in the reanalysis.

Date	Normal high	Normal low	Reanalysis high	Reanalysis low	Chance wet
May 1	30°C	21°C	37°C 1998	20°C 1997	60%
May 2	30°C	21°C	36°C 2012	19°C 1996	59%
May 3	30°C	21°C	35°C 1998	18°C 1999	57%
May 4	30°C	21°C	36°C 2012	18°C 2004	54%
May 5	30°C	21°C	37°C 1998	19°C 2019	51%
May 6	30°C	21°C	36°C 1998	19°C 2018	48%
May 7	30°C	21°C	36°C 2012	19°C 2019	46%
May 8	31°C	21°C	37°C 2016	19°C 1991	43%
May 9	31°C	21°C	36°C 1998	19°C 2007	41%
May 10	31°C	21°C	35°C 2015	19°C 2007	39%
May 11	31°C	21°C	36°C 1998	18°C 2007	38%
May 12	31°C	21°C	37°C 2012	18°C 1997	37%
May 13	31°C	21°C	37°C 1998	19°C 1996	37%
May 14	31°C	21°C	37°C 1998	19°C 2002	36%
May 15	31°C	21°C	37°C 1998	19°C 2003	36%
May 16	31°C	21°C	36°C 2016	20°C 1996	36%
May 17	31°C	21°C	36°C 1998	19°C 2001	37%
May 18	31°C	21°C	37°C 1998	19°C 1999	36%
May 19	31°C	21°C	36°C 2016	19°C 2007	36%
May 20	31°C	21°C	36°C 1998	18°C 1996	36%
May 21	31°C	21°C	37°C 2012	18°C 1996	36%
May 22	31°C	21°C	36°C 2012	18°C 1996	35%
May 23	31°C	21°C	37°C 2016	20°C 1996	35%
May 24	31°C	21°C	36°C 2012	18°C 1996	35%
May 25	31°C	21°C	36°C 2015	19°C 2000	34%
May 26	31°C	21°C	37°C 1998	19°C 2000	33%
May 27	31°C	21°C	38°C 1998	19°C 2007	32%
May 28	32°C	21°C	37°C 1998	19°C 2000	31%
May 29	32°C	21°C	37°C 1998	18°C 1999	30%
May 30	32°C	21°C	37°C 1998	17°C 1999	28%
May 31	32°C	21°C	35°C 2015	19°C 1999	27%

Chance of rain

Chance of a wet day

Sunrise and sunset

Times for 2026, local time (GMT-3).

May 1: sunrise 5:46 AM, sunset 5:41 PM
May 31: sunrise 5:49 AM, sunset 5:39 PM

Every day of May: sun and moon

Other months

Sources

Cloud, humidity, wind and sunshine, and temperature and precipitation: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.