This report describes the typical weather at the Francisco Sá Carneiro Airport (Porto, Portugal) weather station over the course of an average June. It is based on the historical records from 1974 to 2012. Earlier records are either unavailable or unreliable.
Porto has a mediterranean climate with dry warm summers and mild winters. The area within 25 mi of this station is covered by oceans and seas (46%), grasslands (32%), croplands (18%), and shrublands (3%).
The month of June is characterized by gradually rising daily high temperatures, with daily highs around 71°F throughout the month, exceeding 82°F or dropping below 63°F only one day in ten.
Over the course of June, the length of the day is essentially constant. The shortest day of the month is June 1 with 14:57 hours of daylight; the longest day is June 21 with 15:09 hours of daylight.
The earliest sunrise is at 6:01am on June 14; the latest sunset is at 9:12pm on June 27; the latest sunrise is at 6:06am on June 30; the earliest sunset is at 9:01pm on June 1.
Daylight savings time is observed in 2012 but it neither starts nor ends in June, so the entire month is in daylight time.
The median cloud cover ranges from 39% (mostly clear) to 46% (partly cloudy). The trend is for the sky to be clearing with the median cloud cover decreasing by 7% from the start to the end of the month.
On June 15, a representative day, the sky is clear or mostly clear 45% of the time, partly cloudy 26% of the time, and mostly cloudy or overcast 21% of the time.
The probability that precipitation will be observed at this location varies throughout the month. Precipitation is most likely around June 1, occurring in 38% of days. Precipitation is least likely around June 30, occurring in 27% of days.
Throughout June, the most common forms of precipitation are moderate rain, light rain, drizzle, and thunderstorms.
Moderate rain is the most severe precipitation observed during 46% of those days with precipitation. It is most likely around June 1, when it is observed during 19% of all days.
Light rain is the most severe precipitation observed during 21% of those days with precipitation. It is most likely around June 3, when it is observed during 8% of all days.
Drizzle is the most severe precipitation observed during 19% of those days with precipitation. It is most likely around June 27, when it is observed during 7% of all days.
Thunderstorms are the most severe precipitation observed during 12% of those days with precipitation. They are most likely around June 1, when it is observed during 5% of all days.
Either snow is exceptionally unlikely to fall at this location in June or this station does not reliably report precipitation types.
The relative humidity typically ranges from 59% (mildly humid) to 97% (very humid) over the course of a typical June, rarely dropping below 36% (comfortable) and reaching as high as 100% (very humid).
The air is driest around June 15, at which time the relative humidity drops below 70% (mildly humid) three days out of four; it is most humid around June 30, rising above 95% (very humid) three days out of four.
Dew point is often a better measure of how comfortable a person will find the weather than relative humidity because it more directly relates to whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid.
Over the course of a typical June, the dew point typically varies from 50°F (dry) to 61°F (comfortable) and is rarely below 44°F (dry) or above 65°F (mildy humid).
The time of the month between June 1 and June 30 is the most comfortable, with dew points that are neither too dry nor too muggy.
Over the course of June typical wind speeds vary from 0 mph to 14 mph (calm to moderate breeze), rarely exceeding 20 mph (fresh breeze).
The highest average wind speed of 7 mph (light breeze) occurs around June 1, at which time the average daily maximum wind speed is 14 mph (moderate breeze).
The lowest average wind speed of 7 mph (light breeze) occurs around June 29, at which time the average daily maximum wind speed is 14 mph (moderate breeze).