This report describes the typical weather at the Phoenix Deer Valley Airport (Phoenix, Arizona, United States) weather station over the course of an average April 18. It is based on the historical records from 1997 to 2012. Earlier records are either unavailable or unreliable.
Phoenix, Arizona has a hot desert climate. The area within 25 mi of this station is covered by shrublands (86%), grasslands (8%), built-up areas (3%), and croplands (2%).
The temperature typically varies from 59°F to 81°F and is rarely below 51°F or above 91°F.
The coolest hours of the day are from 2am to 8am with the coldest at 6am, at which time the temperature is below 63°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 76°F three days out of four.
The day has gained half its heat by 10am and lost it again by 10pm.
On April 18 the Sun rises at 5:53am and sets at 7:02pm.
Solar noon is at 12:27pm.
For reference, on the longest day of the year the Sun rises at 5:18am and sets at 7:41pm, while on the shortest day of the year it rises at 7:29am and sets at 5:24pm.
Astronomical twilight begins and ends 88 minutes before sunrise and after sunset at 4:25am and 8:30pm, respectively.
Nautical twilight begins and ends 56 minutes before sunrise and after sunset at 4:57am and 7:58pm, respectively.
Civil twilight begins and ends 26 minutes before sunrise and after sunset at 5:27am and 7:27pm, respectively.
Solar twilight begins and ends 33 minutes after sunrise and before sunset at 6:26am and 6:28pm, respectively.
The median cloud cover is 0% (clear) and does not vary substantially over the course of the day.
On average, the sky is clear or mostly clear 85% of the time, partly cloudy 3% of the time, and mostly cloudy or overcast 7% of the time.
There is a 9% chance that precipitation will be observed at some point during the day.
The average measured liquid-equivalent quantity of precipitation is 0.006". Among only those days for which there is at least some measured precipitation, the average is 0.163" and the total rarely exceeds 0.167".
When precipitation does occur it is most often in the form of slight rain (41% of days with precipitation have at worst slight rain), moderate rain (25%), thunderstorms (25%), and heavy rain (9%).
Precipitation is most likely around 4pm and least likely around 11pm.
Either snow is exceptionally unlikely to fall at this location on April 18 or this station does not reliably report precipitation types.
The relative humidity typically ranges from 17% (dry) to 36% (comfortable), rarely dropping below 8% (very dry), or exceeding 55% (mildly humid).
The air is driest at 4pm, at which time the relative humidity is less than 20% (dry) three days out of four; it is most humid at 5am, exceeding 25% (dry) three days out of four.
The dew point ranges from 27°F to 32°F with an average of 30°F.
For reference, comfortable indoor conditions should have a relative humidity between 30% and 50% with a dew point of less than 65°F.
Sustained wind speeds typically vary from 5 mph to 12 mph (light breeze to gentle breeze) over the course of the day.
The peak sustained wind speed typically occurs around 6pm and is rarely outside the range 5 mph to 20 mph (light breeze to fresh breeze).
The wind is most calm around 7am, rarely exceeding 9 mph (gentle breeze).
The wind is most often out of the south west (20% of the time) and west (11% of the time). The wind is least often out of the north west (3% of the time) and north (5% of the time).