This report describes the typical weather at the Trenton-Mercer Airport (Trenton, New Jersey, United States) weather station over the course of an average April 26. It is based on the historical records from 1984 to 2012. Earlier records are either unavailable or unreliable.

Trenton, New Jersey has a humid continental climate with hot summers and no dry season. The area within 25 mi of this station is covered by forests (54%), croplands (24%), built-up areas (18%), and grasslands (3%).

The temperature typically varies from 48°F to 64°F and is rarely below 39°F or above 77°F.

Temperature

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Average hourly temperature (black) with percentil bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).

The coolest hours of the day are from 2am to 8am with the coldest at 6am, at which time the temperature is below 52°F three days out of four.

The warmest hours of the day are from noon to 7pm with the hottest at 4pm, at which time the temperature is above 58°F three days out of four.

The day has gained half its heat by 10am and lost it again by 10pm.

Temperature Bands

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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).

On April 26 the Sun rises at 6:04am and sets at 7:50pm.

Solar noon is at 12:57pm.

For reference, on the longest day of the year the Sun rises at 5:29am and sets at 8:32pm, while on the shortest day of the year it rises at 7:19am and sets at 4:36pm.

Astronomical twilight begins and ends 102 minutes before sunrise and after sunset at 4:22am and 9:32pm, respectively.

Nautical twilight begins and ends 64 minutes before sunrise and after sunset at 5:00am and 8:54pm, respectively.

Civil twilight begins and ends 29 minutes before sunrise and after sunset at 5:35am and 8:19pm, respectively.

Solar twilight begins and ends 37 minutes after sunrise and before sunset at 6:41am and 7:12pm, respectively.

Solar Elevation

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Elevation of the Sun above (positive) or below (negative) the horizon (black line). Yellow and gray fills indicate day and night, respectively. Light gray lines are the corresponding curves for the winter and summer equinoxes.

The median cloud cover ranges from 40% (partly cloudy) to 72% (partly cloudy).

At 2am, the clearest time of the day, the sky is clear, mostly clear, or partly cloudy 37% of the time, and overcast or mostly cloudy 29% of the time.

At 3pm, the cloudiest time of the day, the sky is overcast, mostly cloudy, or partly cloudy 61% of the time, and clear or mostly clear 39% of the time.

The sky is typically clearing in earnest by 10pm.

The clouds have typically started forming in earnest by 7am.

Median Cloud Cover

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Median hourly cloud coverage fraction (black line) with percentile bands (inner band from 40th to 60th percentile, outer band from 25th to 75th percentile).

Cloud Cover Types

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 the United States clear skies are often reported ambiguously, leading them to be lumped in with the missing data.

There is a 47% chance that precipitation will be observed at some point during the day.

The average measured liquid-equivalent quantity of precipitation is 0.046". Among only those days for which there is at least some measured precipitation, the average is 0.221" and the total rarely exceeds 0.521".

Probability of Precipitation

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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.

When precipitation does occur it is most often in the form of slight rain (49% of days with precipitation have at worst slight rain), moderate rain (22%), thunderstorms (15%), and heavy rain (6%).

Precipitation is most likely around 3pm and least likely around 2am.

Types of Precipitation

Relative frequency of various types of precipitation over the course of a typical April 26.

Either snow is exceptionally unlikely to fall at this location on April 26 or this station does not reliably report precipitation types.

The relative humidity typically ranges from 57% (mildly humid) to 79% (humid), rarely dropping below 28% (dry), or exceeding 100% (very humid).

The air is driest at 4pm, at which time the relative humidity is less than 78% (humid) three days out of four; it is most humid at 5am, exceeding 67% (mildly humid) three days out of four.

Relative Humidity

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Average hourly humidity (black line) with percentile bands (inner bands from 25th to 75th percentile, outer bands from 10th to 90th percentile).

The dew point ranges from 40°F to 42°F with an average of 41°F.

For reference, comfortable indoor conditions should have a relative humidity between 30% and 50% with a dew point of less than 65°F.

Dew Point

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Average hourly dew point (black line) with percentile bands (inner bands from 25th to 75th percentile, outer bands from 10th to 90th percentile).

Sustained wind speeds typically vary from 6 mph to 12 mph (light breeze to gentle breeze) over the course of the day.

The peak sustained wind speed typically occurs around 3pm and is rarely outside the range 6 mph to 18 mph (light breeze to fresh breeze).

The wind is most calm around 6am, rarely exceeding 12 mph (gentle breeze).

Wind Speed

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Average hourly wind speed (black line) with percentile bands (inner bands from 25th to 75th percentile, outer bands from 10th to 90th percentile).

The wind is most often out of the north west (13% of the time), north (12% of the time), and west (12% of the time). The wind is least often out of the south east (5% of the time).

Wind Directions

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

Wind Directions Over Day

The fraction of time spent with the wind blowing from the various directions on an hourly basis. Values do not sum to 100% because the wind direction is undefined when the wind speed is zero.