KMDW — CHICAGO
Chicago, IL, US · America/Chicago · 41.7860°, -87.7524° · 188m elevation
Daily METAR Observations
| Time | Temperature | Dew Point | Humidity | Wind | Wind Speed | Wind Gust | Pressure | Precip. | Condition |
|---|---|---|---|---|---|---|---|---|---|
| 12:53 AM | 69 °F 69.1 °F 21 °C 20.6 °C | 59 °F 59 °F 15 °C 15 °C | 70 % | SW | 6 mph 5 kt 9 km/h | 0 mph 0 kt 0 km/h | 29.96 in | 0.0 in | Fair |
| METAR KMDW 130553Z 23005KT 10SM CLR 21/15 A2996 RMK AO2 SLP135 T02060150 10261 20206 402780161 50012 | |||||||||
| 1:53 AM | 67 °F 66.9 °F 19 °C 19.4 °C | 59 °F 59 °F 15 °C 15 °C | 76 % | SSW | 7 mph 6 kt 11 km/h | 0 mph 0 kt 0 km/h | 29.95 in | 0.0 in | Fair |
| METAR KMDW 130653Z 21006KT 10SM CLR 19/15 A2995 RMK AO2 SLP132 T01940150 | |||||||||
| 2:53 AM | 66 °F 66 °F 19 °C 18.9 °C | 59 °F 59 °F 15 °C 15 °C | 78 % | SW | 6 mph 5 kt 9 km/h | 0 mph 0 kt 0 km/h | 29.94 in | 0.0 in | Fair |
| METAR KMDW 130753Z 22005KT 10SM CLR 19/15 A2994 RMK AO2 SLP129 T01890150 | |||||||||
| 3:53 AM | 66 °F 66 °F 19 °C 18.9 °C | 59 °F 59 °F 15 °C 15 °C | 78 % | SSW | 6 mph 5 kt 9 km/h | 0 mph 0 kt 0 km/h | 29.94 in | 0.0 in | Fair |
| METAR KMDW 130853Z 21005KT 10SM CLR 19/15 A2994 RMK AO2 SLP130 T01890150 55005 | |||||||||
| 4:53 AM | 65 °F 64.9 °F 18 °C 18.3 °C | 59 °F 59 °F 15 °C 15 °C | 81 % | SSW | 7 mph 6 kt 11 km/h | 0 mph 0 kt 0 km/h | 29.95 in | 0.0 in | Fair |
| METAR KMDW 130953Z 21006KT 10SM FEW160 18/15 A2995 RMK AO2 SLP133 T01830150 | |||||||||
| 5:53 AM | 65 °F 64.9 °F 18 °C 18.3 °C | 59 °F 59 °F 15 °C 15 °C | 81 % | SSW | 7 mph 6 kt 11 km/h | 0 mph 0 kt 0 km/h | 29.95 in | 0.0 in | Partly Cloudy |
| METAR KMDW 131053Z 21006KT 10SM SCT160 SCT250 18/15 A2995 RMK AO2 SLP134 T01830150 | |||||||||
| 6:53 AM | 68 °F 68 °F 20 °C 20 °C | 59 °F 59 °F 15 °C 15 °C | 73 % | SSW | 7 mph 6 kt 11 km/h | 0 mph 0 kt 0 km/h | 29.96 in | 0.0 in | Fair |
| METAR KMDW 131153Z 21006KT 10SM FEW160 FEW250 20/15 A2996 RMK AO2 SLP136 T02000150 10206 20178 51006 | |||||||||
| 7:53 AM | 72 °F 72 °F 22 °C 22.2 °C | 58 °F 57.9 °F 14 °C 14.4 °C | 61 % | SSW | 13 mph 11 kt 20 km/h | 0 mph 0 kt 0 km/h | 29.95 in | 0.0 in | Fair |
| METAR KMDW 131253Z 21011KT 10SM FEW160 FEW250 22/14 A2995 RMK AO2 SLP134 T02220144 | |||||||||
| 8:53 AM | 76 °F 75.9 °F 24 °C 24.4 °C | 58 °F 57.9 °F 14 °C 14.4 °C | 54 % | SW | 15 mph 13 kt 24 km/h | 24 mph 21 kt 39 km/h | 29.93 in | 0.0 in | Fair |
| METAR KMDW 131353Z 22013G21KT 10SM FEW250 24/14 A2993 RMK AO2 SLP124 T02440144 | |||||||||
| 9:53 AM | 78 °F 78.1 °F 26 °C 25.6 °C | 57 °F 57 °F 14 °C 13.9 °C | 48 % | SW | 17 mph 15 kt 28 km/h | 27 mph 23 kt 43 km/h | 29.92 in | 0.0 in | Partly Cloudy |
| METAR KMDW 131453Z 22015G23KT 10SM SCT250 26/14 A2992 RMK AO2 PK WND 20032/1358 SLP121 T02560139 58014 | |||||||||
| 10:53 AM | 80 °F 80.1 °F 27 °C 26.7 °C | 59 °F 59 °F 15 °C 15 °C | 49 % | SW | 18 mph 16 kt 30 km/h | 31 mph 27 kt 50 km/h | 29.91 in | 0.0 in | Mostly Cloudy |
| METAR KMDW 131553Z 22016G27KT 10SM FEW045 FEW100 BKN250 27/15 A2991 RMK AO2 PK WND 22028/1529 SLP121 T02670150 | |||||||||
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 | 5:13 AM / 8:28 PM |
| Civil Twilight | 4:41 AM / 9:00 PM | |
| Nautical Twilight | 3:57 AM / 9:44 PM | |
| Astronomical Twilight | 3:04 AM / 10:37 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.