This report describes the historical weather record at the Greater Rochester International Airport (Rochester, New York, United States) during 1964. This station has records back to January 1948.
Rochester, New York has a humid continental climate with warm summers and no dry season. The area within 25 mi of this station is covered by forests (62%), oceans and seas (19%), grasslands (11%), and built-up areas (7%)
Daylight saving time (DST) was observed at Rochester, New York during 1964. There were two time changes during 1964:
1964 was a leap year and thus has 366 days rather than the normal 365. Leap years occur every fourth year and the extra day is always February 29th. In 1964 February 29th falls on a Saturday.
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 1964 they occurred on:
|Spring Equinox||Friday, 20 March 1964.|
|Summer Solstice||Sunday, 21 June 1964.|
|Fall Equinox||Wednesday, 23 September 1964.|
|Winter Solstice||Monday, 21 December 1964.|
The hottest day of 1964 was July 28, with a high temperature of 97°F. For reference, on that day the average high temperature is 81°F and the high temperature exceeds 89°F only one day in ten. The hottest month of 1964 was July with an average daily high temperature of 84°F.
Relative to the average, the hottest day was December 26. The high temperature that day was 59°F, compared to the average of 34°F, a difference of 25°F. In relative terms the warmest month was January, with an average high temperature of 36°F, compared to an typical value of 31°F.
The longest warm spell was from July 16 to July 30, constituting 15 consecutive days with warmer than average high temperatures. The month of January had the largest fraction of warmer than average days with 71% days with higher than average high temperatures.
The coldest day of 1964 was January 1, with a low temperature of -5°F. For reference, on that day the average low temperature is 21°F and the low temperature drops below 7°F only one day in ten. The coldest month of 1964 was February with an average daily low temperature of 16°F.
Relative to the average, the coldest day was January 1. The low temperature that day was -5°F, compared to the average of 21°F, a difference of 26°F. In relative terms the coldest month was August, with an average low temperature of 56°F, compared to an typical value of 60°F.
The longest cold spell was from August 4 to August 23, constituting 20 consecutive days with cooler than average low temperatures. The month of August had the largest fraction of cooler than average days with 81% days with lower than average low temperatures.
The longest freezing spell was from January 11 to January 17, constituting 7 consecutive days with temperatures strictly below freezing.
The clearest month of 1964 was July, with 61% of days being more clear than cloudy. The longest spell of clear weather was from August 27 to September 4, constituting 9 consecutive days that were clearer than they were cloudy.
The cloudiest month of 1964 was December, with 68% of days being more cloudy than clear. The longest spell of cloudy weather was from December 20 to December 31, constituting 12 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 August 21. That day saw 0.984" of liquid (or liquid equivalent) precipitation, compared to a median value of 0.137". The month with the most precipitation was April, with 3.583", compared to a median value of 2.591".
As determined by quantitative measurements, the longest dry spell was from August 27 to September 9, constituting 14 consecutive days with no measured precipitation. The month with the largest fraction of dry days was June, with 77% of days reporting no measured precipitation at all.
The month with the largest fraction of days with at least some measured precipitation was December, with 58% 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 1964 with the most precipitation observations was December 4. There were 22 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 December, with 273 hourly present weather reports involving some form of precipitation.
As determined by the present weather reports, the longest dry spell was from July 4 to July 12, constituting 9 consecutive days with no observed precipitation. The month with the largest fraction of days without observed precipitation was September, with 70% of days reporting no observed precipitation at all.
The month with the largest fraction of days with at least some observed precipitation was December, with 90% 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 1964 with the largest number of those reports was April, with a total of 102 reports. The day with the largest number of those reports was April 20, with a total of 21 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 1964 was on October 10; the last was on April 9. The month of 1964 with the largest number of those reports was December, with a total of 200 reports. The day with the largest number of those reports was December 6, with a total of 21 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 1964 was July with an average daily low humidity of 40%, and the most humid month was December with an average daily low humidity of 69%.
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 1964, January had 31 dry days, no comfortable days, and no humid days; April had 20 dry days, 10 comfortable days, and no humid days; July had 1 dry day, 17 comfortable days, and 13 humid days; and October had 25 dry days, 6 comfortable days, and no humid days.
The highest sustained wind speed was 44 mph, occurring on March 5; the highest daily mean wind speed was 26 mph (January 10);
The windiest month was January, with an average wind speed of 14 mph. The least windy month was July, with an average wind speed of 8 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 1964 with the lowest average visibility was August 21, with an average visibility of 2.9 mi. The month with the lowest average visibility was December, with an average visibility of 8.2 mi. With an average visibility of 12.8 mi, the month of May had the highest average visibility.
This station did not reliably report the cloud ceiling during 1964.