Climate and Average Weather Year Round in Castro Brazil

In Castro, the summers are long, warm, and mostly cloudy; the winters are short, cool, and partly cloudy; and it is wet year round. Over the course of the year, the temperature typically varies from 50°F to 80°F and is rarely below 41°F or above 86°F.

Based on the tourism score, the best times of year to visit Castro for warm-weather activities are from early March to mid May and from late October to mid December.

The warm season lasts for 4.5 months, from November 18 to April 3, with an average daily high temperature above 78°F. The hottest month of the year in Castro is January, with an average high of 80°F and low of 64°F.

The cool season lasts for 2.8 months, from May 13 to August 7, with an average daily high temperature below 70°F. The coldest month of the year in Castro is July, with an average low of 50°F and high of 67°F.

In Castro, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.

The clearer part of the year in Castro begins around March 8 and lasts for 6.8 months, ending around October 1.

The clearest month of the year in Castro is August, during which on average the sky is clear, mostly clear, or partly cloudy 61% of the time.

The cloudier part of the year begins around October 1 and lasts for 5.2 months, ending around March 8.

The cloudiest month of the year in Castro is February, during which on average the sky is overcast or mostly cloudy 62% of the time.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Castro varies significantly throughout the year.

The wetter season lasts 5.5 months, from October 1 to March 17, with a greater than 40% chance of a given day being a wet day. The month with the most wet days in Castro is January, with an average of 17.9 days with at least 0.04 inches of precipitation.

The drier season lasts 6.5 months, from March 17 to October 1. The month with the fewest wet days in Castro is August, with an average of 6.7 days with at least 0.04 inches of precipitation.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. The month with the most days of rain alone in Castro is January, with an average of 17.9 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 59% on February 8.

Rainfall

To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. Castro experiences significant seasonal variation in monthly rainfall.

Rain falls throughout the year in Castro. The month with the most rain in Castro is January, with an average rainfall of 6.4 inches.

The month with the least rain in Castro is August, with an average rainfall of 2.8 inches.

The length of the day in Castro varies over the course of the year. In 2024, the shortest day is June 20, with 10 hours, 36 minutes of daylight; the longest day is December 21, with 13 hours, 41 minutes of daylight.

The earliest sunrise is at 5:22 AM on November 30, and the latest sunrise is 1 hour, 43 minutes later at 7:05 AM on July 3. The earliest sunset is at 5:38 PM on June 7, and the latest sunset is 1 hour, 36 minutes later at 7:14 PM on January 13.

Daylight saving time (DST) is not observed in Castro during 2024.

The figure below presents a compact representation of key lunar data for 2024. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases.

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

Castro experiences significant seasonal variation in the perceived humidity.

The muggier period of the year lasts for 5.6 months, from October 26 to April 12, during which time the comfort level is muggy, oppressive, or miserable at least 9% of the time. The month with the most muggy days in Castro is January, with 9.6 days that are muggy or worse.

The month with the fewest muggy days in Castro is July, with 0.0 days that are muggy or worse.

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed in Castro does not vary significantly over the course of the year, remaining within 0.4 miles per hour of 3.3 miles per hour throughout.

The predominant average hourly wind direction in Castro varies throughout the year.

The wind is most often from the north for 1.3 months, from June 7 to July 15, with a peak percentage of 40% on June 23. The wind is most often from the east for 11 months, from July 15 to June 7, with a peak percentage of 46% on January 1.

To characterize how pleasant the weather is in Castro throughout the year, we compute two travel scores.

The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best times of year to visit Castro for general outdoor tourist activities are from early March to mid May and from late October to mid December, with a peak score in the last week of March.

The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Castro for hot-weather activities is from late November to early April, with a peak score in the second week of March.

Methodology

For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.

Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.

Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.

Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.

Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

While it does not do so every year, freezing temperatures are seen in Castro over some winters. The day least likely to be in the growing season is July 12, with a 77% chance.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.

Based on growing degree days alone, the first spring blooms in Castro should appear around July 12, only rarely appearing before July 9 or after July 16.

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

The average daily incident shortwave solar energy experiences significant seasonal variation over the course of the year.

The brighter period of the year lasts for 3.5 months, from October 20 to February 5, with an average daily incident shortwave energy per square meter above 6.3 kWh. The brightest month of the year in Castro is December, with an average of 6.8 kWh.

The darker period of the year lasts for 2.6 months, from May 11 to July 30, with an average daily incident shortwave energy per square meter below 4.3 kWh. The darkest month of the year in Castro is June, with an average of 3.7 kWh.

For the purposes of this report, the geographical coordinates of Castro are -24.789 deg latitude, -50.012 deg longitude, and 3,235 ft elevation.

The topography within 2 miles of Castro contains significant variations in elevation, with a maximum elevation change of 495 feet and an average elevation above sea level of 3,296 feet. Within 10 miles contains significant variations in elevation (978 feet). Within 50 miles contains very significant variations in elevation (3,707 feet).

The area within 2 miles of Castro is covered by trees (35%), cropland (25%), shrubs (22%), and grassland (18%), within 10 miles by trees (43%) and cropland (37%), and within 50 miles by trees (57%) and cropland (27%).