Average Weather In May For Rome, Italy

Location

This report describes the typical weather at the Rome Urbe Airport (Rome, Italy) weather station over the course of an average May. It is based on the historical records from 1998 to 2012. Earlier records are either unavailable or unreliable.

Rome has a mediterranean climate with dry hot summers and mild winters. The area within 25 mi of this station is covered by shrublands (47%), croplands (22%), forests (18%), and oceans and seas (10%).

Temperature

The month of May is characterized by rising daily high temperatures, with daily highs increasing from 72°F to 79°F over the course of the month, exceeding 86°F or dropping below 66°F only one day in ten.

Daily High and Low Temperature in May

The daily average low (blue) and high (red) temperature with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).
Daily low temperatures range from 52°F to 60°F, falling below 47°F or exceeding 65°F only one day in ten.

Fraction of Time Spent in Various Temperature Bands in May

The average fraction of time spent in various temperature bands: frigid (below 15°F), freezing (15°F to 32°F), cold (32°F to 50°F), cool (50°F to 65°F), comfortable (65°F to 75°F), warm (75°F to 85°F), hot (85°F to 100°F) and sweltering (above 100°F).

Sun

Over the course of May, the length of the day is gradually increasing. From the start to the end of the month, the length of the day increases by 58 minutes, implying an average day-over-day increase of 1.9 minutes.

The shortest day of the month is May 1 with 14:03 hours of daylight; the longest day is May 31 with 15:01 hours of daylight.

Daily Hours of Daylight and Twilight in May

The number of hours during which the Sun is visible (black line), with various degrees of daylight, twilight, and night, indicated by the color bands. From bottom (most yellow) to top (most gray): full daylight, solar twilight (Sun is visible but less than 6° from the horizon), civil twilight (Sun is not visible but is less than 6° below the horizon), nautical twilight (Sun is between 6° and 12° below the horizon), astronomical twilight (Sun is between 12° and 18° below the horizon), and full night.

The earliest sunrise is at 5:38am on May 30; the latest sunset is at 8:38pm on May 31; the latest sunrise is at 6:06am on May 1; the earliest sunset is at 8:09pm on May 1.

Daylight saving time is observed in 2012 but it neither starts nor ends in May, so the entire month is in daylight time.

Daily Sunrise & Sunset with Twilight and Daylight Saving Time in May

The solar day over the course of the year 2012 . From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (solar, civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray. The transitions to and from daylight saving time are indicated by the "DST" labels.

Clouds

The median cloud cover ranges from 47% (partly cloudy) to 54% (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.

Median Cloud Cover in May

The median daily cloud cover (black line) with percentile bands (inner band from 40th to 60th percentile, outer band from 25th to 75th percentile).

On May 16, a representative day, the sky is clear or mostly clear 13% of the time, partly cloudy 17% of the time, and mostly cloudy or overcast 12% of the time.

Cloud Cover Types in May

The fraction of time spent in each of the five sky cover categories. From top (most blue) to bottom (most gray), the categories are clear, mostly clear, partly cloudy, mostly cloudy, and overcast. Pink indicates missing data. Outside of the United States clear skies are often reported ambiguously, leading them to be lumped in with the missing data.

Precipitation

The probability that precipitation will be observed at this location varies throughout the month. Precipitation is most likely around May 7, occurring in 31% of days. Precipitation is least likely around May 31, occurring in 23% of days.

Probability of Precipitation at Some Point in the Day in May

The fraction of days in which various types of precipitation are observed. If more than one type of precipitation is reported in a given day, the more severe precipitation is counted. For example, if light rain is observed in the same day as a thunderstorm, that day counts towards the thunderstorm totals. The order of severity is from the top down in this graph, with the most severe at the bottom.

Throughout May, the most common forms of precipitation are thunderstorms, light rain, and moderate rain.

Thunderstorms are the most severe precipitation observed during 43% of those days with precipitation. They are most likely around May 10, when it is observed during 13% of all days.

Light rain is the most severe precipitation observed during 29% of those days with precipitation. It is most likely around May 1, when it is observed during 10% of all days.

Moderate rain is the most severe precipitation observed during 23% of those days with precipitation. It is most likely around May 4, when it is observed during 8% of all days.

Types of Precipitation Throughout May

Relative frequency of various types of precipitation over the course of a typical May.

Snow

Either snow is exceptionally unlikely to fall at this location in May or this station does not reliably report precipitation types.

Humidity

The relative humidity typically ranges from 45% (comfortable) to 93% (very humid) over the course of a typical May, rarely dropping below 32% (comfortable) and reaching as high as 100% (very humid).

The air is driest around May 31, at which time the relative humidity drops below 51% (mildly humid) three days out of four; it is most humid around May 1, rising above 90% (very humid) three days out of four.

Relative Humidity in May

The average daily high (blue) and low (brown) relative humidity with percentile bands (inner bands from 25th to 75th percentile, outer bands from 10th to 90th percentile).

Dew Point

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 May, the dew point typically varies from 47°F (dry) to 62°F (comfortable) and is rarely below 40°F (dry) or above 67°F (muggy).

The time of the month between May 1 and May 31 is the most comfortable, with dew points that are neither too dry nor too muggy.

Dew Point in May

The daily average low (blue) and high (red) dew point with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).

Wind

Over the course of May typical wind speeds vary from 0 mph to 11 mph (calm to gentle breeze), rarely exceeding 16 mph (moderate breeze).

The highest average wind speed of 4 mph (light breeze) occurs around May 30, at which time the average daily maximum wind speed is 11 mph (gentle breeze).

The lowest average wind speed of 4 mph (light breeze) occurs around May 3, at which time the average daily maximum wind speed is 10 mph (gentle breeze).

Wind Speed in May

The average daily minimum (red), maximum (green), and average (black) wind speed with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).
The wind direction is highly variable and is not predominantly from any single direction.The wind is least often out of the north east (1% of the time), east (2% of the time), south east (2% of the time), north west (2% of the time), and west (4% of the time).

Wind Directions in May

The fraction of time spent with the wind blowing from the various directions over the entire year. Values do not sum to 100% because the wind direction is undefined when the wind speed is zero.

Fraction of Time Spent with Various Wind Directions in May

The fraction of time spent with the wind blowing from the various directions on a daily basis. Stacked values do not always sum to 100% because the wind direction is undefined when the wind speed is zero.