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 | 62 °F 62.1 °F 17 °C 16.7 °C | 59 °F 59 °F 15 °C 15 °C | 90 % | SW | 4 mph 3 kt 6 km/h | 0 mph 0 kt 0 km/h | 29.96 in | 0.0 in | Fair |
| METAR KARR 130552Z AUTO 23003KT 10SM CLR 17/15 A2996 RMK AO2 SLP141 T01670150 10256 20161 402670144 50003 | |||||||||
| 1:52 AM | 62 °F 62.1 °F 17 °C 16.7 °C | 60 °F 60.1 °F 16 °C 15.6 °C | 93 % | SSW | 6 mph 5 kt 9 km/h | 0 mph 0 kt 0 km/h | 29.95 in | 0.0 in | Fair |
| METAR KARR 130652Z AUTO 21005KT 10SM CLR 17/16 A2995 RMK AO2 SLP137 T01670156 | |||||||||
| 2:52 AM | 62 °F 62.1 °F 17 °C 16.7 °C | 59 °F 59 °F 15 °C 15 °C | 90 % | SW | 5 mph 4 kt 7 km/h | 0 mph 0 kt 0 km/h | 29.94 in | 0.0 in | Fair |
| METAR KARR 130752Z AUTO 22004KT 10SM CLR 17/15 A2994 RMK AO2 SLP134 T01670150 | |||||||||
| 3:52 AM | 62 °F 62.1 °F 17 °C 16.7 °C | 59 °F 59 °F 15 °C 15 °C | 90 % | SW | 6 mph 5 kt 9 km/h | 0 mph 0 kt 0 km/h | 29.94 in | 0.0 in | Fair |
| METAR KARR 130852Z AUTO 22005KT 10SM CLR 17/15 A2994 RMK AO2 SLP135 T01670150 55005 | |||||||||
| 4:52 AM | 60 °F 60.1 °F 16 °C 15.6 °C | 58 °F 57.9 °F 14 °C 14.4 °C | 93 % | SW | 4 mph 3 kt 6 km/h | 0 mph 0 kt 0 km/h | 29.95 in | 0.0 in | Fair |
| METAR KARR 130952Z AUTO 23003KT 10SM CLR 16/14 A2995 RMK AO2 SLP138 T01560144 | |||||||||
| 5:52 AM | 59 °F 59 °F 15 °C 15 °C | 57 °F 57 °F 14 °C 13.9 °C | 93 % | N | 0 mph 0 kt 0 km/h | 0 mph 0 kt 0 km/h | 29.96 in | 0.0 in | Fair |
| METAR KARR 131052Z AUTO 00000KT 10SM CLR 15/14 A2996 RMK AO2 SLP141 T01500139 | |||||||||
| 6:52 AM | 65 °F 64.9 °F 18 °C 18.3 °C | 60 °F 60.1 °F 16 °C 15.6 °C | 84 % | SSW | 6 mph 5 kt 9 km/h | 0 mph 0 kt 0 km/h | 29.96 in | 0.0 in | Fair |
| METAR KARR 131152Z 21005KT 10SM CLR 18/16 A2996 RMK AO2 SLP141 T01830156 10183 20144 51006 | |||||||||
| 7:52 AM | 69 °F 69.1 °F 21 °C 20.6 °C | 60 °F 60.1 °F 16 °C 15.6 °C | 73 % | SSW | 12 mph 10 kt 19 km/h | 0 mph 0 kt 0 km/h | 29.95 in | 0.0 in | Fair |
| METAR KARR 131252Z 21010KT 10SM CLR 21/16 A2995 RMK AO2 SLP137 T02060156 | |||||||||
| 8:52 AM | 73 °F 73 °F 23 °C 22.8 °C | 61 °F 61 °F 16 °C 16.1 °C | 66 % | SW | 13 mph 11 kt 20 km/h | 21 mph 18 kt 33 km/h | 29.93 in | 0.0 in | Fair |
| METAR KARR 131352Z 22011G18KT 10SM CLR 23/16 A2993 RMK AO2 SLP129 T02280161 | |||||||||
| 9:52 AM | 78 °F 78.1 °F 26 °C 25.6 °C | 61 °F 61 °F 16 °C 16.1 °C | 56 % | SSW | 15 mph 13 kt 24 km/h | 23 mph 20 kt 37 km/h | 29.93 in | 0.0 in | Fair |
| METAR KARR 131452Z 20013G20KT 10SM CLR 26/16 A2993 RMK AO2 SLP129 T02560161 56012 | |||||||||
| 10:52 AM | 80 °F 80.1 °F 27 °C 26.7 °C | 62 °F 62.1 °F 17 °C 16.7 °C | 54 % | SSW | 13 mph 11 kt 20 km/h | 0 mph 0 kt 0 km/h | 29.93 in | 0.0 in | Fair |
| METAR KARR 131552Z 21011KT 10SM CLR 27/17 A2993 RMK AO2 SLP130 T02670167 | |||||||||
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 | 15h 14m | 5:16 AM / 8:31 PM |
| Civil Twilight | 4:44 AM / 9:03 PM | |
| Nautical Twilight | 4:00 AM / 9:47 PM | |
| Astronomical Twilight | 3:07 AM / 10:40 PM | |
| Moon: New Moon | ||
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.