Historical Weather For 1967 in Philadelphia, Pennsylvania, USA

Location

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%)

Calendar

Daylight saving time (DST) was observed at Philadelphia, Pennsylvania during 1967. There were two time changes during 1967:

  • DST started on Sunday April 30, 1967 at 3:00 am, from EST (GMT-5) to EDT (GMT-4).
  • DST ended on Sunday October 29, 1967 at 1:00 am, from EDT (GMT-4) to EST (GMT-5).

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.

Temperature

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.

Temperature

The daily low (blue) and high (red) temperature during 1967 with the area between them shaded gray and superimposed over the corresponding averages (thick lines), and with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile). The bar at the top of the graph is red where both the daily high and low are above average, blue where they are both below average, and white otherwise.

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.

Hourly Temperature Bands

The full year of hourly temperature reports with the days of the year on the horizontal and the hours of the day on the vertical. The hourly temperature measurement is color coded into meaningful temperature bands: frigid is purple (below 15°F), freezing is blue (15°F to 32°F), cold is dark green (32°F to 50°F), cool is light green (50°F to 65°F), comfortable is yellow (65°F to 75°F), warm is light red (75°F to 85°F), hot is medium red (85°F to 100°F), sweltering is dark red (above 100°F), and missing data is pink.

Clouds

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.

Cloud Coverage

The fraction of time spent in each of the five sky cover categories over the course of 1967 on a daily basis. 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 of the United States clear skies are often reported ambiguously, leading them to be lumped in with the missing data. The bar at the top of the graph is gray if the sky was cloudy or mostly cloudy for more than half the day, blue if it is clear or mostly clear for more than half the day, and blue-gray otherwise.

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.

Hourly Cloud Coverage

The full year of hourly cloud coverage reports with the days of the year on the horizontal and the hours of the day on the vertical. The sky cover is color coded: from most blue to most gray, the categories are clear, mostly clear, partly cloudy, mostly cloudy, and overcast. Pink indicates missing data. Outside of the United States clear skies are often reported ambiguously, leading them to be lumped in with the missing data.

Precipitation

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.

Liquid Equivalent Quantity

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.

Precipitation Quantity

The daily measured quantity of liquid (or liquid equivalent in the case of solid precipitation) precipitation over the course of 1967, with the median non-zero quantity (thick gray line) and 10th, 25th, 75th, and 90th non-zero percentiles (shaded areas). The bar at the top of the graph is green if any precipitation was measured that day and white otherwise.

Present Weather Reports

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.

Precipitation Reports

The daily number of hourly observed precipitation reports during 1967, color coded according to precipitation type, and stacked in order of severity. From the bottom up, the categories are thunderstorms (orange); heavy, moderate, and light snow (dark to light blue); heavy, moderate, and light rain (dark to light green); and drizzle (lightest green). Not all categories are necessarily present in this particular graph. The faint shaded areas indicate climate normals. The bar at the top of the graph is green if any precipitation was observed that day and white otherwise.

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.

Hourly Weather Reports

The full year of hourly present weather reports with the days of the year on the horizontal and the hours of the day on the vertical. The color-coded categories are thunderstorms (orange); heavy, moderate, and light snow (dark to light blue); heavy, moderate, and light rain (dark to light green); drizzle (lightest green); freezing rain and sleet (light and dark cyan); snow grains (lightest blue); hail (red); fog (gray); and haze (brownish gray).

Liquid Precipitation Reports

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.

Liquid Precipitation Reports

The daily number of hourly observed liquid precipitation reports (including thunderstorms) during 1967, with climate normals (faint shaded areas). The bar at the top of the graph is green if any liquid precipitation was observed that day and white otherwise.

Snow

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.

Reports

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.

Snow Reports

The daily number of hourly observed snow reports during 1967, with climate normals (faint shaded areas). The bar at the top of the graph is blue if there was snow fall observed that day and white otherwise.

Humidity

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.

Humidity

The daily low (brown) and high (blue) relative humidity during 1967 with the area between them shaded gray and superimposed over the corresponding averages (thick lines), and with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).

Dew 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.

Dew Point

The daily low (blue) and high (red) dew point during 1967 with the area between them shaded gray and superimposed over the corresponding averages (thick lines), and with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).

Wind

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.

Wind Speed

The daily low and high wind speed (light gray area) and the maximum daily wind gust speed (tiny blue dashes).

Visibility

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.

Visibility

The daily average visibility, depicted as gray bars encroaching down from the top of the graph.

Cloud Ceiling

This station did not reliably report the cloud ceiling during 1967.