This report describes the historical weather record at the Philadelphia International Airport (Philadelphia, Pennsylvania, United States) during 1967. This station has records back to December 1947.
Philadelphia, Pennsylvania has a warm humid temperate climate with hot summers and no dry season. The area within 25 mi of this station is covered by croplands (32%), built-up areas (30%), forests (29%), grasslands (6%), and lakes and rivers (3%)
Daylight saving time (DST) was observed at Philadelphia, Pennsylvania during 1967. There were two time changes during 1967:
1967 was not a leap year, so it has 365 days and no February 29th. The first leap year before 1967 was 1964 and the first after was 1968.
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 1967 they occurred on:
|Spring Equinox||Tuesday, 21 March 1967.|
|Summer Solstice||Thursday, 22 June 1967.|
|Fall Equinox||Saturday, 23 September 1967.|
|Winter Solstice||Friday, 22 December 1967.|
The hottest day of 1967 was June 24, with a high temperature of 93°F. For reference, on that day the average high temperature is 84°F and the high temperature exceeds 91°F only one day in ten. The hottest month of 1967 was July with an average daily high temperature of 85°F.
Relative to the average, the hottest day was January 24. The high temperature that day was 68°F, compared to the average of 39°F, a difference of 29°F. In relative terms the warmest month was January, with an average high temperature of 43°F, compared to an typical value of 40°F.
The longest warm spell was from June 2 to June 14, constituting 13 consecutive days with warmer than average high temperatures. The month of June had the largest fraction of warmer than average days with 70% days with higher than average high temperatures.
The coldest day of 1967 was February 9, with a low temperature of 4°F. For reference, on that day the average low temperature is 26°F and the low temperature drops below 15°F only one day in ten. The coldest month of 1967 was February with an average daily low temperature of 22°F.
Relative to the average, the coldest day was March 19. The low temperature that day was 12°F, compared to the average of 36°F, a difference of 24°F. In relative terms the coldest month was May, with an average low temperature of 47°F, compared to an typical value of 55°F.
The longest cold spell was from May 21 to June 10, constituting 21 consecutive days with cooler than average low temperatures. The month of May had the largest fraction of cooler than average days with 94% days with lower than average low temperatures.
The clearest month of 1967 was September, with 47% of days being more clear than cloudy. The longest spell of clear weather was from September 2 to September 9, constituting 8 consecutive days that were clearer than they were cloudy.
The cloudiest month of 1967 was July, with 71% of days being more cloudy than clear. The longest spell of cloudy weather was from August 19 to August 29, constituting 11 consecutive days that were cloudier than they were 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 June 22. That day saw 2.469" of liquid (or liquid equivalent) precipitation, compared to a median value of 0.161". The month with the most precipitation was August, with 7.315", compared to a median value of 3.295".
As determined by quantitative measurements, the longest dry spell was from May 30 to June 18, constituting 20 consecutive days with no measured precipitation. The month with the largest fraction of dry days was October, with 90% of days reporting no measured precipitation at all.
The month with the largest fraction of days with at least some measured precipitation was August, with 52% 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 1967 with the most precipitation observations was March 5. There were 23 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 March, with 175 hourly present weather reports involving some form of precipitation.
As determined by the present weather reports, the longest dry spell was from May 30 to June 18, constituting 20 consecutive days with no observed precipitation. The month with the largest fraction of days without observed precipitation was June, with 80% of days reporting no observed precipitation at all.
The month with the largest fraction of days with at least some observed precipitation was March, with 55% of days reporting some observed precipitation.
In this section we consider only those weather reports that indicate liquid precipitation. For the purposes of this analysis, we include thunderstorms even though some thunderstorms are not accompanied by liquid precipitation.
The month of 1967 with the largest number of those reports was March, with a total of 109 reports. The day with the largest number of those reports was March 6, with a total of 22 reports.
This station reports when snow is observed falling but does not report the quantity of snow that has fallen or the depth of snow on the ground.
In this section we consider hourly weather reports that contain an observation of falling snow. These reports do not necessarily correspond to accumulation.
The first reported snow fall in 1967 was on November 9; the last was on April 27. The month of 1967 with the largest number of those reports was February, with a total of 88 reports. The day with the largest number of those reports was February 17, with a total of 18 reports.
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 1967 was April with an average daily low humidity of 40%, and the most humid month was January with an average daily low humidity of 55%.
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 1967, January had 28 dry days, 3 comfortable days, and no humid days; April had 20 dry days, 10 comfortable days, and no humid days; July had no dry days, 6 comfortable days, and 25 humid days; and October had 14 dry days, 17 comfortable days, and no humid days.
The highest sustained wind speed was 37 mph, occurring on February 16; the highest daily mean wind speed was 21 mph (February 25);
The windiest month was February, with an average wind speed of 11 mph. The least windy month was July, with an average wind speed of 7 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 1967 with the lowest average visibility was August 26, with an average visibility of 1.9 mi. The month with the lowest average visibility was July, with an average visibility of 6.0 mi. With an average visibility of 10.4 mi, the month of April had the highest average visibility.
This station did not reliably report the cloud ceiling during 1967.