This report describes the historical weather record at the Chicago Midway International Airport (Chicago, Illinois, United States) during 1949. This station has records back to January 1948.
Chicago, Illinois has a humid continental climate with hot summers and no dry season. The area within 25 mi of this station is covered by built-up areas (36%), oceans and seas (24%), grasslands (23%), croplands (14%), and forests (3%)
Daylight saving time (DST) was observed at Chicago, Illinois during 1949. There were two time changes during 1949:
1949 was not a leap year, so it has 365 days and no February 29th. The first leap year before 1949 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 1949 they occurred on:
|Spring Equinox||Sunday, 20 March 1949.|
|Summer Solstice||Tuesday, 21 June 1949.|
|Fall Equinox||Friday, 23 September 1949.|
|Winter Solstice||Thursday, 22 December 1949.|
The hottest day of 1949 was July 3, with a high temperature of 102°F. For reference, on that day the average high temperature is 83°F and the high temperature exceeds 92°F only one day in ten. The hottest month of 1949 was July with an average daily high temperature of 87°F.
Relative to the average, the hottest day was January 15. The high temperature that day was 60°F, compared to the average of 30°F, a difference of 30°F. In relative terms the warmest month was October, with an average high temperature of 67°F, compared to an typical value of 62°F.
The longest warm spell was from June 18 to July 10, constituting 23 consecutive days with warmer than average high temperatures. The month of July had the largest fraction of warmer than average days with 77% days with higher than average high temperatures.
The coldest day of 1949 was January 30, with a low temperature of -4°F. For reference, on that day the average low temperature is 18°F and the low temperature drops below 2°F only one day in ten. The coldest month of 1949 was February with an average daily low temperature of 20°F.
Relative to the average, the coldest day was January 30. The low temperature that day was -4°F, compared to the average of 18°F, a difference of 22°F. In relative terms the coldest month was September, with an average low temperature of 50°F, compared to an typical value of 58°F.
The longest cold spell was from August 29 to September 12, constituting 15 consecutive days with cooler than average low temperatures. The month of September had the largest fraction of cooler than average days with 87% days with lower than average low temperatures.
The clearest month of 1949 was April, with 53% of days being more clear than cloudy. The longest spell of clear weather was from August 20 to August 27, constituting 8 consecutive days that were clearer than they were cloudy.
The cloudiest month of 1949 was January, with 71% of days being more cloudy than clear. The longest spell of cloudy weather was from May 14 to May 23, constituting 10 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 December 21. That day saw 2.043" of liquid (or liquid equivalent) precipitation, compared to a median value of 0.103". The month with the most precipitation was December, with 6.724", compared to a median value of 2.071".
As determined by quantitative measurements, the longest dry spell was from May 2 to May 15, constituting 14 consecutive days with no measured precipitation. The month with the largest fraction of dry days was November, with 80% 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 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 1949 with the most precipitation observations was April 15. 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 January, with 195 hourly present weather reports involving some form of precipitation.
As determined by the present weather reports, the longest dry spell was from June 4 to June 13, constituting 10 consecutive days with no observed precipitation. The month with the largest fraction of days without observed precipitation was July, with 68% of days reporting no observed precipitation at all.
The month with the largest fraction of days with at least some observed precipitation was January, with 65% 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 1949 with the largest number of those reports was January, with a total of 110 reports. The day with the largest number of those reports was December 21, with a total of 19 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 1949 was on November 2; the last was on April 24. The month of 1949 with the largest number of those reports was January, with a total of 85 reports. The day with the largest number of those reports was March 9, 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 1949 was April with an average daily low humidity of 39%, and the most humid month was January with an average daily low humidity of 64%.
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 1949, January had 29 dry days, 2 comfortable days, and no humid days; April had 25 dry days, 5 comfortable days, and no humid days; July had no dry days, 11 comfortable days, and 20 humid days; and October had 16 dry days, 14 comfortable days, and 1 humid day.
The highest sustained wind speed was 36 mph, occurring on April 23; the highest daily mean wind speed was 21 mph (January 6);
The windiest month was November, with an average wind speed of 12 mph. The least windy month was August, 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 1949 with the lowest average visibility was January 4, with an average visibility of 1.4 mi. The month with the lowest average visibility was January, with an average visibility of 6.5 mi. With an average visibility of 10.7 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 1949 with the lowest average cloud ceiling was January 14, with an average cloud ceiling of 233'. The month with the lowest average cloud ceiling was January, with an average cloud ceiling of 5641'. The month of June has the highest average cloud ceiling, with an average cloud ceiling of 12179'.