KSFO — SAN FRANCISCO
San Francisco, CA, US · America/Los_Angeles · 37.6190°, -122.3749° · 3m elevation
Daily METAR Observations
| Time | Temperature | Dew Point | Humidity | Wind | Wind Speed | Wind Gust | Pressure | Precip. | Condition |
|---|---|---|---|---|---|---|---|---|---|
| 12:56 AM | 53 °F 53.1 °F 12 °C 11.7 °C | 49 °F 48.9 °F 9 °C 9.4 °C | 86 % | W | 6 mph 5 kt 9 km/h | 0 mph 0 kt 0 km/h | 30.00 in | 0.02 in | Light Rain |
| METAR KSFO 050756Z 26005KT 10SM -RA FEW009 OVC080 12/09 A3000 RMK AO2 SLP157 P0002 T01170094 401780117 | |||||||||
| 1:56 AM | 53 °F 53.1 °F 12 °C 11.7 °C | 50 °F 50 °F 10 °C 10 °C | 89 % | W | 6 mph 5 kt 9 km/h | 0 mph 0 kt 0 km/h | 29.99 in | 0.04 in | Light Rain |
| METAR KSFO 050856Z 28005KT 10SM -RA FEW007 OVC070 12/10 A2999 RMK AO2 SLP155 P0004 60007 T01170100 50000 | |||||||||
| 2:56 AM | 54 °F 54 °F 12 °C 12.2 °C | 50 °F 50 °F 10 °C 10 °C | 86 % | W | 12 mph 10 kt 19 km/h | 0 mph 0 kt 0 km/h | 29.97 in | 0.01 in | Light Rain |
| METAR KSFO 050956Z 26010KT 10SM -RA FEW009 BKN060 OVC080 12/10 A2997 RMK AO2 RAE11B35 SLP150 P0001 T01220100 | |||||||||
| 3:56 AM | 54 °F 54 °F 12 °C 12.2 °C | 50 °F 50 °F 10 °C 10 °C | 86 % | W | 13 mph 11 kt 20 km/h | 0 mph 0 kt 0 km/h | 29.97 in | 0.01 in | Overcast |
| METAR KSFO 051056Z 27011KT 10SM FEW009 BKN044 OVC060 12/10 A2997 RMK AO2 RAE16 SLP149 P0000 T01220100 | |||||||||
| 4:56 AM | 54 °F 54 °F 12 °C 12.2 °C | 48 °F 48 °F 9 °C 8.9 °C | 80 % | SW | 8 mph 7 kt 13 km/h | 0 mph 0 kt 0 km/h | 29.96 in | 0.0 in | Overcast |
| METAR KSFO 051156Z 23007KT 10SM FEW009 BKN042 OVC060 12/09 A2996 RMK AO2 SLP146 60008 70008 T01220089 10122 20117 56010 | |||||||||
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 | 13h 57m | 6:07 AM / 8:04 PM |
| Civil Twilight | 5:40 AM / 8:31 PM | |
| Nautical Twilight | 5:05 AM / 9:06 PM | |
| Astronomical Twilight | 4:28 AM / 9:43 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.