KARR — CHICAGO/AURORA
Chicago/Aurora, IL, US · America/Chicago · 41.7700°, -88.4800° · 215m elevation
Daily METAR Observations
| Time | Temperature | Dew Point | Humidity | Wind | Wind Speed | Wind Gust | Pressure | Precip. | Condition |
|---|---|---|---|---|---|---|---|---|---|
| 12:52 AM | 55 °F 55 °F 13 °C 12.8 °C | 37 °F 37 °F 3 °C 2.8 °C | 51 % | WNW | 8 mph 7 kt 13 km/h | 0 mph 0 kt 0 km/h | 29.62 in | 0.0 in | Overcast |
| METAR KARR 050552Z AUTO 30007KT 9SM OVC095 13/03 A2962 RMK AO2 SLP026 T01280028 10194 20128 402720056 51019 | |||||||||
| 1:52 AM | 52 °F 52 °F 11 °C 11.1 °C | 36 °F 36 °F 2 °C 2.2 °C | 54 % | WNW | 8 mph 7 kt 13 km/h | 0 mph 0 kt 0 km/h | 29.63 in | 0.0 in | Partly Cloudy |
| METAR KARR 050652Z AUTO 30007KT 9SM SCT100 11/02 A2963 RMK AO2 SLP029 T01110022 | |||||||||
| 2:52 AM | 52 °F 52 °F 11 °C 11.1 °C | 36 °F 36 °F 2 °C 2.2 °C | 54 % | NW | 8 mph 7 kt 13 km/h | 0 mph 0 kt 0 km/h | 29.65 in | 0.0 in | Mostly Cloudy |
| METAR KARR 050752Z AUTO 31007KT 9SM BKN110 11/02 A2965 RMK AO2 SLP036 T01110022 | |||||||||
| 3:52 AM | 52 °F 52 °F 11 °C 11.1 °C | 36 °F 36 °F 2 °C 2.2 °C | 54 % | NW | 10 mph 9 kt 17 km/h | 0 mph 0 kt 0 km/h | 29.70 in | 0.0 in | Overcast |
| METAR KARR 050852Z AUTO 32009KT 9SM OVC100 11/02 A2970 RMK AO2 SLP054 T01110022 53027 | |||||||||
| 4:52 AM | 50 °F 50 °F 10 °C 10 °C | 35 °F 35.1 °F 2 °C 1.7 °C | 56 % | N | 8 mph 7 kt 13 km/h | 0 mph 0 kt 0 km/h | 29.72 in | 0.01 in | Overcast |
| METAR KARR 050952Z AUTO 35007KT 10SM OVC100 10/02 A2972 RMK AO2 RAB25E34 SLP061 P0000 T01000017 | |||||||||
| 5:52 AM | 50 °F 50 °F 10 °C 10 °C | 31 °F 30.9 °F -1 °C -0.6 °C | 48 % | N | 9 mph 8 kt 15 km/h | 0 mph 0 kt 0 km/h | 29.73 in | 0.0 in | Overcast |
| METAR KARR 051052Z AUTO 01008KT 10SM OVC095 10/M01 A2973 RMK AO2 SLP067 T01001006 | |||||||||
| 6:52 AM | 46 °F 46 °F 8 °C 7.8 °C | 37 °F 37 °F 3 °C 2.8 °C | 71 % | N | 14 mph 12 kt 22 km/h | 0 mph 0 kt 0 km/h | 29.81 in | 0.02 in | Light Rain |
| METAR KARR 051152Z 35012KT 6SM -RA OVC044 08/03 A2981 RMK AO2 RAB1059 SLP092 P0002 60002 70003 T00780028 10128 20078 53036 | |||||||||
Time Series
Summary
| Temperature (°F) Temperature (°C) | Actual | |
| High Temp | ||
| Low Temp | ||
| Day Average Temp | ||
| Precipitation (in) | Actual | |
| Precipitation | ||
| Dew Point (°F) Dew Point (°C) | Actual | |
| High | ||
| Low | ||
| Average | ||
| Humidity (%) | Actual | |
| Average Humidity | ||
| Wind (mph) Wind (kt) Wind (km/h) | Actual | |
| Max Wind Speed | ||
| Max Wind Gust | ||
| Visibility | ||
| Pressure (in) | Actual | |
| Average Pressure | ||
| Astronomy | Day Length | Rise / Set |
| Actual Time | 14h 14m | 5:43 AM / 7:57 PM |
| Civil Twilight | 5:14 AM / 8:27 PM | |
| Nautical Twilight | 4:36 AM / 9:05 PM | |
| Astronomical Twilight | 3:54 AM / 9:46 PM | |
| Moon: Waning Gibbous | ||
Methodology
Day Boundaries & Time
A "day" is defined as midnight to midnight (00:00:00 through 23:59:59) in the station's local time, using the IANA timezone assigned to each station (e.g. America/Chicago, Europe/London). Daylight Saving Time transitions are respected automatically — when a station's local clocks spring forward or fall back, the UTC boundaries of the day shift accordingly. This means a "day" in the spring DST transition is 23 hours, and in the fall transition it is 25 hours. All observations are stored internally in UTC and converted to local time for display.
Temperature
The FAA reports temperature in degrees Celsius. Values are stored to one decimal place — if a source value has additional precision, it is rounded on storage. Fahrenheit values are computed as °F = °C × 9/5 + 32. All temperatures are displayed as whole numbers (rounded to the nearest integer) in both Celsius and Fahrenheit. High and low temperatures are the maximum and minimum observed values for the day. The day average is the arithmetic mean of all observed temperatures, rounded to the nearest whole number.
Dew Point & Relative Humidity
Dew point is stored and displayed using the same rounding method as temperature (whole numbers). Relative humidity is not reported directly in METARs — it is calculated from the temperature and dew point using the Magnus formula: RH = 100 × exp[(17.27 × Td)/(237.7 + Td) − (17.27 × T)/(237.7 + T)], where T is temperature and Td is dew point, both in °C. The result is rounded to the nearest whole percent and clamped between 0% and 100%.
Wind
Wind direction is reported in degrees true (0–360). The compass direction shown (N, NNE, NE, etc.) divides the compass into 16 sectors of 22.5° each. Variable winds (reported as "VRB" in the METAR) are displayed as "CALM". Wind speed is reported in knots (integer). Miles per hour is computed as mph = kt × 1.15078 and kilometers per hour as km/h = kt × 1.852, both displayed as whole numbers. Wind gust is shown only when the METAR includes a gust value.
Pressure
The altimeter setting is reported in inches of mercury (inHg) to two decimal places. This is the station pressure corrected to sea level and is the value displayed. When the METAR also includes sea level pressure in millibars, that value is used in daily summary calculations.
Precipitation
Precipitation accumulations (1-hour, 3-hour, 6-hour, and 24-hour) are included when reported by the station. A value of 0.0005 inches represents trace precipitation in the FAA convention. The daily total in the summary is the sum of all 1-hour accumulations that exceed trace. Not all stations report precipitation data.
Sky Condition & Weather
The "Condition" column is derived from two METAR fields. If a weather phenomena code is present (e.g. RA for rain, SN for snow, FG for fog, TSRA for thunderstorms), it takes priority and the intensity prefix (- for light, + for heavy) is included. When no active weather is reported, the condition is derived from the highest sky cover layer: CLR/SKC/FEW = Fair, SCT = Partly Cloudy, BKN = Mostly Cloudy, OVC = Overcast.