This report describes the historical weather record at the Tucson International Airport (Tucson, Arizona, United States) during 2013. This station has records back to October 1948.
Tucson, Arizona has a hot semi-arid steppe climate. The area within 25 mi of this station is covered by shrublands (70%), grasslands (23%), forests (4%), and built-up areas (3%)
Daylight saving time (DST) was not observed at Tucson, Arizona during 2013.
2013 was not a leap year, so it has 365 days and no February 29th. The first leap year before 2013 was 2012 and the first after was 2016.
The summer and winter solstices and the spring and fall equinoxes mark the passing of the seasons. They fall on nearly the same day each year, with differences of a day or two depending on the year. In 2013 they occurred on:
|Spring Equinox||Wednesday, 20 March 2013.|
|Summer Solstice||Friday, 21 June 2013.|
|Fall Equinox||Sunday, 22 September 2013.|
|Winter Solstice||Saturday, 21 December 2013.|
The hottest day of 2013 was June 29, with a high temperature of 110°F. For reference, on that day the average high temperature is 102°F and the high temperature exceeds 107°F only one day in ten. The hottest month of 2013 was June with an average daily high temperature of 104°F.
Relative to the average, the hottest day was March 2. The high temperature that day was 96°F, compared to the average of 71°F, a difference of 25°F. In relative terms the warmest month was March, with an average high temperature of 81°F, compared to an typical value of 74°F.
The longest warm spell was from May 30 to July 2, constituting 34 consecutive days with warmer than average high temperatures. The month of June had the largest fraction of warmer than average days with 100% days with higher than average high temperatures.
The coldest day of 2013 was January 15, with a low temperature of 18°F. For reference, on that day the average low temperature is 40°F and the low temperature drops below 32°F only one day in ten. The coldest month of 2013 was January with an average daily low temperature of 37°F.
Relative to the average, the coldest day was July 24. The low temperature that day was 26°F, compared to the average of 75°F, a difference of 49°F. In relative terms the coldest month was February, with an average low temperature of 38°F, compared to an typical value of 43°F.
The longest cold spell was from October 10 to October 23, constituting 14 consecutive days with cooler than average low temperatures. The month of February had the largest fraction of cooler than average days with 68% days with lower than average low temperatures.
The clearest month of 2013 was May, with 100% of days being more clear than cloudy. The longest spell of clear weather was from April 10 to July 20, constituting 102 consecutive days that were clearer than they were cloudy.
The cloudiest month of 2013 was February, with 14% of days being more cloudy than clear.
This station reports both the quantity of liquid precipitation and categorical observations of precipitation (e.g., moderate rain, or heavy snow). Both are subject to erroneous reports, but the former is particularly prone to false reports, especially ones indicating an excessive quantity of precipitation. Please bear this in mind when reading the extrema reported in this section.
The day with the largest quantity of precipitation was November 23. That day saw 1.346" of liquid (or liquid equivalent) precipitation, compared to a median value of 0.133". The month with the most precipitation was July, with 2.707", compared to a median value of 1.699".
As determined by quantitative measurements, the longest dry spell was from May 7 to June 30, constituting 55 consecutive days with no measured precipitation. The month of October were completely without measured precipitation.
The month with the largest fraction of days with at least some measured precipitation was July, with 29% of days reporting some measured precipitation.
This station reports when significant weather events (including precipitation) are visually observed at or near the station. Such events do not always correspond to measured quantities of liquid equivalent precipitation, such as when the event is near by not at the station, or in the case of solid precipitation that does not melt in the collection basin.
The day in 2013 with the most precipitation observations was November 23. There were 13 hourly weather reports that day (out of a maximum of 24) in which some form of precipitation was observated at or near the station. The month with the most precipitation observations was July, with 74 hourly present weather reports involving some form of precipitation.
As determined by the present weather reports, the longest dry spell was from September 11 to November 2, constituting 53 consecutive days with no observed precipitation. The month of October was completely without observed precipitation.
The month with the largest fraction of days with at least some observed precipitation was July, with 58% of days reporting some observed precipitation.
Either snow is exceptionally rare at this location or this station did not reliably report it during 2013.
Humidity is an important factor in determining how weather conditions feel to a person experiencing them. Hot and humid days feel even hotter than hot and dry days because the high level of water content in humid air discourages the evaporation of sweat from a person's skin.
When reading the graph below, keep in mind that the hottest part of the day tends to be the least humid, so the daily low (brown) traces are more relevant for understanding daytime comfort than the daily high (blue) traces, which typically occur during the night. Applying that observation, the least humid month of 2013 was June with an average daily low humidity of 5%, and the most humid month was July with an average daily low humidity of 25%.
But it is important to keep in mind that humidity does not tell the whole picture and the dew point is often a better measure of how comfortable a person will find a given set of weather conditions. Please see the next section for continued discussion of this point.
Dew point is the temperature below which water vapor will condense into liquid water. It is therefore also related to the rate of evaporation of liquid water. Since the evaporation of sweat is an important cooling mechanism for the human body, the dew point is an important measurement for understanding how dry, comfortable, or humid a given set of weather conditions will feel.
Generally speaking, dew points below 50°F will feel a bit dry to some people, but comfortable to people accustomed to dry conditions; dew points from 50°F to 68°F are fairly comfortable to most people, and dew points above 68°F are increasingly uncomfortable, becoming oppressive around 77°F.
To take some examples, and basing our categorization on the daily high dew point in 2013, January had 27 dry days, 4 comfortable days, and no humid days; April had 30 dry days, no comfortable days, and no humid days; July had no dry days, 17 comfortable days, and 14 humid days; and October had 29 dry days, 2 comfortable days, and no humid days.
The highest sustained wind speed was 45 mph, occurring on July 5; the highest daily mean wind speed was 19 mph (November 27); and the highest wind gust speed was 68 mph (June 30).
The windiest month was May, with an average wind speed of 9 mph. The least windy month was December, with an average wind speed of 6 mph.
Visibility is the maximum distance at which a given reference object or light can be clearly discerned. In the United States, visibilities that are greater than or equal to 10 miles are typically reported as 10 miles.
The day of 2013 with the lowest average visibility was November 23, with an average visibility of 7.2 mi. The month with the lowest average visibility was February, with an average visibility of 9.9 mi. With an average visibility of 10.0 mi, the month of March had the highest average visibility.
The cloud ceiling is the altitude of the lowest layer of clouds that are at categorized as broken (mostly cloudy) or overcast (cloudy). If no such cloud layer exists then the ceiling is unlimited and no value is reported.
The day of 2013 with the lowest average cloud ceiling was February 12, with an average cloud ceiling of 1033'. The month with the lowest average cloud ceiling was October, with an average cloud ceiling of 5928'. The month of June has the highest average cloud ceiling, with an average cloud ceiling of 10833'.