This report describes the typical weather at the Grand Canyon National Park Airport (Grand Canyon National Park, Arizona, United States) weather station over the course of an average July. It is based on the historical records from 1981 to 2012. Earlier records are either unavailable or unreliable.
Grand Canyon National Park, Arizona has a continental climate with dry warm summers. The area within 25 mi of this station is covered by shrublands (65%), grasslands (19%), and forests (16%).
The month of July is characterized by gradually falling daily high temperatures, with daily highs around 84°F throughout the month, exceeding 91°F or dropping below 76°F only one day in ten.
Over the course of July, the length of the day is gradually decreasing. The shortest day of the month is July 31 with 13:58 hours of daylight; the longest day is July 1 with 14:33 hours of daylight.
The earliest sunrise is at 5:16am on July 1; the latest sunset is at 7:49pm on July 4; the latest sunrise is at 5:36am on July 31; the earliest sunset is at 7:34pm on July 31.
Daylight saving time (DST) is not observed in 2012.
The median cloud cover ranges from 15% (mostly clear) to 26% (mostly clear). The trend is for the sky to be becoming cloudier with the median cloud cover increasing by 11% from the start to the end of the month.
On July 1, the clearest day of the month, the sky is clear, mostly clear, or partly cloudy 57% of the time, and overcast or mostly cloudy 15% of the time.
On July 31, the cloudiest day of the month, the sky is overcast, mostly cloudy, or partly cloudy 35% of the time, and clear or mostly clear 38% of the time.
The probability that precipitation will be observed at this location varies throughout the month. Precipitation is most likely around July 31, occurring in 37% of days. Precipitation is least likely around July 1, occurring in 24% of days.
Throughout July, the most common forms of precipitation are thunderstorms and light rain.
Thunderstorms are the most severe precipitation observed during 73% of those days with precipitation. They are most likely around July 31, when it is observed during 28% of all days.
Light rain is the most severe precipitation observed during 21% of those days with precipitation. It is most likely around July 30, when it is observed during 7% of all days.
Either snow is exceptionally unlikely to fall at this location in July or this station does not reliably report precipitation types.
The relative humidity typically ranges from 21% (dry) to 93% (very humid) over the course of a typical July, rarely dropping below 8% (very dry) and reaching as high as 100% (very humid).
The air is driest around July 1, at which time the relative humidity drops below 22% (dry) three days out of four; it is most humid around July 31, rising above 91% (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 July, the dew point typically varies from 27°F (dry) to 52°F (very comfortable) and is rarely below 10°F (dry) or above 60°F (comfortable).
Over the course of July typical wind speeds vary from 0 mph to 16 mph (calm to moderate breeze), rarely exceeding 22 mph (fresh breeze).
The highest average wind speed of 6 mph (light breeze) occurs around July 1, at which time the average daily maximum wind speed is 16 mph (moderate breeze).
The lowest average wind speed of 5 mph (light breeze) occurs around July 31, at which time the average daily maximum wind speed is 13 mph (moderate breeze).