This report describes the historical weather record at the Dane County Regional Airport (Madison, Wisconsin, United States) during 1951. This station has records back to January 1948.
Madison, Wisconsin has a humid continental climate with hot summers and no dry season. The area within 25 mi of this station is covered by grasslands (49%), croplands (45%), and lakes and rivers (3%)
Daylight saving time (DST) was observed at Madison, Wisconsin during 1951. There were two time changes during 1951:
1951 was not a leap year, so it has 365 days and no February 29th. The first leap year before 1951 was 1948 and the first after was 1952.
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 1951 they occurred on:
|Spring Equinox||Wednesday, 21 March 1951.|
|Summer Solstice||Friday, 22 June 1951.|
|Fall Equinox||Sunday, 23 September 1951.|
|Winter Solstice||Saturday, 22 December 1951.|
The hottest day of 1951 was July 24, with a high temperature of 93°F. For reference, on that day the average high temperature is 83°F and the high temperature exceeds 90°F only one day in ten. The hottest month of 1951 was July with an average daily high temperature of 82°F.
Relative to the average, the hottest day was December 3. The high temperature that day was 60°F, compared to the average of 35°F, a difference of 25°F. In relative terms the warmest month was May, with an average high temperature of 72°F, compared to an typical value of 69°F.
The longest warm spell was from January 9 to January 21, constituting 13 consecutive days with warmer than average high temperatures. The month of May had the largest fraction of warmer than average days with 65% days with higher than average high temperatures.
The coldest day of 1951 was January 30, with a low temperature of -36°F. For reference, on that day the average low temperature is 11°F and the low temperature drops below -7°F only one day in ten. The coldest month of 1951 was January with an average daily low temperature of 5°F.
Relative to the average, the coldest day was January 30. The low temperature that day was -36°F, compared to the average of 11°F, a difference of 47°F. In relative terms the coldest month was November, with an average low temperature of 20°F, compared to an typical value of 28°F.
The longest cold spell was from January 21 to February 11, constituting 22 consecutive days with cooler than average low temperatures. The month of June had the largest fraction of cooler than average days with 73% days with lower than average low temperatures.
The longest freezing spell was from December 12 to December 29, constituting 18 consecutive days with temperatures strictly below freezing.
The clearest month of 1951 was July, with 48% of days being more clear than cloudy. The longest spell of clear weather was from October 8 to October 14, constituting 7 consecutive days that were clearer than they were cloudy.
The cloudiest month of 1951 was April, with 70% of days being more cloudy than clear. The longest spell of cloudy weather was from March 27 to April 3, constituting 8 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 July 21. That day saw 1.394" of liquid (or liquid equivalent) precipitation, compared to a median value of 0.168". The month with the most precipitation was October, with 5.417", compared to a median value of 1.978".
As determined by quantitative measurements, the longest dry spell was from July 22 to August 5, constituting 15 consecutive days with no measured precipitation. The month with the largest fraction of dry days was July, 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 April, with 53% 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 1951 with the most precipitation observations was March 13. 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 December, with 179 hourly present weather reports involving some form of precipitation.
As determined by the present weather reports, the longest dry spell was from July 28 to August 5, constituting 9 consecutive days with no observed precipitation. The month with the largest fraction of days without observed precipitation was July, with 65% of days reporting no observed precipitation at all.
The month with the largest fraction of days with at least some observed precipitation was April, with 77% 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 1951 with the largest number of those reports was April, with a total of 129 reports. The day with the largest number of those reports was February 16, with a total of 20 reports.
This station reports both when snow is observed to be falling and the measured depth of the snow on the ground. Both are subject to erroneous reports, but the latter is significantly less reliable. Please bear this in mind when reading this section.
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 1951 was on October 23; the last was on April 17. The month of 1951 with the largest number of those reports was December, with a total of 167 reports. The day with the largest number of those reports was March 13, with a total of 22 reports.
Snow depth on the ground is an optional and inconsistently reported part of standard weather reports. It is rarely reported more often than every six hours, it is often skipped, it is often reported erroneously, and a snow depth of zero is normally not distinguished from a missing report. These issues (particularly the last one) make it hard to collect statistics on snow depth with any confidence. To overcome this issue, we base our statistics on only those reports with present non-zero measurements of snow depth. Reports that fail to mention snow that is present, and reports that do not report snow depth because there is no snow on the ground are excluded because they cannot be distinguished from one another.
The first reported accumulation in 1951 was on November 4. The last day of the snow season with snow reported on the ground was April 1. The day with the deepest snow depth was January 6, with an average snow depth of 16.9" over the course of the day. The longest stretch of time during which there was always snow on the ground was from January 1 to March 5 (64 consecutive days).
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 1951 was May with an average daily low humidity of 45%, and the most humid month was February with an average daily low humidity of 63%.
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 1951, January had 31 dry days, no comfortable days, and no humid days; April had 26 dry days, 4 comfortable days, and no humid days; July had no dry days, 21 comfortable days, and 10 humid days; and October had 18 dry days, 12 comfortable days, and 1 humid day.
The highest sustained wind speed was 55 mph, occurring on July 8; the highest daily mean wind speed was 30 mph (March 18); and the highest wind gust speed was 49 mph (March 3).
The windiest month was March, with an average wind speed of 17 mph. The least windy month was August, 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 1951 with the lowest average visibility was November 30, with an average visibility of 0.1 mi. The month with the lowest average visibility was February, with an average visibility of 7.4 mi. With an average visibility of 13.1 mi, the month of September 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 1951 with the lowest average cloud ceiling was October 1, with an average cloud ceiling of 37'. The month with the lowest average cloud ceiling was December, with an average cloud ceiling of 5902'. The month of June has the highest average cloud ceiling, with an average cloud ceiling of 12825'.