Altadena weather
Temperature, rain and wind in Altadena (California, United States), a city of about 42,777 people: how it is right now, hour by hour into tomorrow, the next 7 days and what each month of the year is like.
This page is not in Google’s index: the city is small, or it gets the same forecast as a large city next to it.
Right now
Thursday 15 October, 20:00 (America/Los_Angeles)
71 °F
Clear sky
Feels like
68 °F
Humidity
35%
Wind
18 mph
WSW · Beaufort 5
Dew point
42 °F
Cloud cover
0%
Pressure
1,015 hPa
Hour by hour
Next 24 hours, in the city’s local time.
| Time | Conditions | Temperature | Rain | Wind |
|---|---|---|---|---|
| 19:00 | Clear sky | 72 °F | 0.00 in | 17 mph |
| 20:00 | Clear sky | 71 °F | 0.00 in | 18 mph |
| 21:00 | Clear sky | 70 °F | 0.00 in | 16 mph |
| 22:00 | Clear sky | 68 °F | 0.00 in | 16 mph |
| 23:00 | Clear sky | 67 °F | 0.00 in | 18 mph |
| 00:00 | Clear sky | 67 °F | 0.00 in | 18 mph |
| 01:00 | Clear sky | 66 °F | 0.00 in | 18 mph |
| 02:00 | Clear sky | 65 °F | 0.00 in | 18 mph |
| 03:00 | Clear sky | 65 °F | 0.00 in | 16 mph |
| 04:00 | Clear sky | 64 °F | 0.00 in | 17 mph |
| 05:00 | Clear sky | 63 °F | 0.00 in | 19 mph |
| 06:00 | Clear sky | 64 °F | 0.00 in | 18 mph |
| 07:00 | Clear sky | 65 °F | 0.00 in | 17 mph |
| 08:00 | Clear sky | 69 °F | 0.00 in | 18 mph |
| 09:00 | Clear sky | 76 °F | 0.00 in | 16 mph |
| 10:00 | Clear sky | 80 °F | 0.00 in | 17 mph |
| 11:00 | Clear sky | 83 °F | 0.00 in | 17 mph |
| 12:00 | Clear sky | 85 °F | 0.00 in | 16 mph |
| 13:00 | Clear sky | 87 °F | 0.00 in | 15 mph |
| 14:00 | Clear sky | 88 °F | 0.00 in | 15 mph |
| 15:00 | Clear sky | 88 °F | 0.00 in | 14 mph |
| 16:00 | Clear sky | 87 °F | 0.00 in | 13 mph |
| 17:00 | Clear sky | 85 °F | 0.00 in | 13 mph |
| 18:00 | Clear sky | 79 °F | 0.00 in | 13 mph |
Next 7 days
| Day | Conditions | Low | High | Rain outlook |
|---|---|---|---|---|
| Thu 15/10 | Clear sky | 63 °F | 72 °F | no rain expected · 0.00 in |
| Fri 16/10 | Clear sky | 63 °F | 88 °F | no rain expected · 0.00 in |
| Sat 17/10 | Clear sky | 65 °F | 87 °F | no rain expected · 0.00 in |
| Mon 19/10 | Clear sky | 60 °F | 80 °F | no rain expected · 0.00 in |
| Tue 20/10 | Clear sky | 57 °F | 78 °F | rain unlikely · 0.01 in |
| Wed 21/10 | Light rain showers | 55 °F | 64 °F | rain likely · 0.57 in |
| Thu 22/10 | Clear sky | 47 °F | 65 °F | rain possible · 0.05 in |
This column is our own reading: the global model does not publish a probability of precipitation for this region, so we classify the day from the forecast symbol and the total in millimetres. It is not an official probability figure.
America/Los_Angeles
What each number means
- Rain (mm)
- 1 millimetre of rain is 1 litre of water per square metre. Up to 2 mm in a day is drizzle; from 10 mm it is proper rain; more than 50 mm in a few hours is the amount that floods streets.
- Humidity
- Relative humidity is how much water vapour the air holds compared with the most it can hold at that temperature. Above 80% sweat evaporates slowly and heat feels worse; below 30% your throat and eyes dry out.
- Dew point
- The dew point is the temperature at which the air would start to condense. The closer it is to the air temperature, the muggier it feels. Above 20 °C the air already feels heavy.
- Feels like
- "Feels like" combines temperature, wind and humidity: strong wind carries heat away from the body, so it feels colder than the thermometer; high humidity in the heat makes it feel warmer.
- Wind
- Wind is given as a speed and the direction it blows from. Up to 20 km/h you barely notice it; at 40 km/h it moves branches and parasols; above 60 km/h it brings down trees and roof tiles.
- Cloud cover
- Cloud cover as a percentage is how much of the sky is covered. Up to 20% is a clear sky; above 80% the sun barely gets through.
- Chance of rain
- The model does not publish a probability of precipitation for this region. This column is our own reading: the global model does not publish a probability of precipitation for this region, so we classify the day from the forecast symbol and the total in millimetres. It is not an official probability figure.
Month-by-month climate
In October, Altadena averages 67 °F and about 0.67 in of rain over the month, on the 25-year Meteorological and Solar Monthly & Annual Climatologies (January 2001 - December 2025) climatology.
Warmest month
August
Coldest month
December
Wettest month
February
Driest month
June
| Month | Mean temperature | Rain | Mean humidity |
|---|---|---|---|
| January | 54 °F | 2.9 in | 59% |
| February | 54 °F | 3.0 in | 63% |
| March | 57 °F | 1.7 in | 64% |
| April | 59 °F | 0.75 in | 63% |
| May | 64 °F | 0.35 in | 62% |
| June | 69 °F | 0.04 in | 57% |
| July | 74 °F | 0.08 in | 52% |
| August | 75 °F | 0.04 in | 49% |
| September | 73 °F | 0.12 in | 50% |
| October | 67 °F | 0.67 in | 52% |
| November | 60 °F | 0.98 in | 53% |
| December | 53 °F | 2.6 in | 58% |
Frequently asked questions
- Will it rain tomorrow in Altadena?
- no rain expected. Rain: 0.00 in. Low 63 °F, High 88 °F.
- What is the temperature in Altadena right now?
- 71 °F, clear sky. Feels like: 68 °F. Humidity: 35%.
- What will the weather be like at the weekend in Altadena?
- Sat 17/10: clear sky, 65 °F / 87 °F, no rain expected.
- Which is the wettest month in Altadena?
- February — ~3.0 in (25-year Meteorological and Solar Monthly & Annual Climatologies (January 2001 - December 2025), NASA POWER).
- How far ahead does this Altadena forecast go?
- This page shows 7 days. The model run used here is from 16/10/2026, 01:18 UTC, and the page fetches a new one every 30 minutes.
Nearby cities
Forecasts for places near Altadena:
- Pasadena 5 km
- La Cañada Flintridge 5 km
- South Pasadena 8 km
- Arcadia 10 km
- Alhambra 11 km
- San Gabriel 11 km
- La Crescenta-Montrose 11 km
- Temple City 11 km
How to read this page
How to read the min and the max
The week’s high (88 °F) arrives in the afternoon, about two hours after solar noon; the low (47 °F) just before sunrise. Both are air temperature in the shade, two metres above ground — in direct sun or over asphalt a thermometer reads higher.
Where this number comes from
The Altadena forecast comes from MET Norway, a partir do ECMWF HRES e, na área nórdica, do MEPS, run of 16/10/2026, 01:18 UTC. The month-by-month climate comes from NASA POWER, climatology of 25-year Meteorological and Solar Monthly & Annual Climatologies (January 2001 - December 2025). Both are credited in full at the foot of this page.
What a forecast cannot promise
Out to two days accuracy is high; by day seven the trend matters more than the exact figure. For Altadena the model publishes no rain probability, so the expectation column is our reading.
Severe weather warnings
This page is informational. For official warnings of storms, gales or flooding affecting Altadena, go to your national weather service through the World Meteorological Organization warning portal.
Understanding the weather and climate of Altadena
Is this week in Altadena above or below the October normal?
The average of the next 7 days in Altadena works out at 67 °F, against a normal of 67 °F for October over 25-year Meteorological and Solar Monthly & Annual Climatologies (January 2001 - December 2025). The gap is under one degree, so the week sits squarely inside what the season normally brings.
Within the week the highest maximum lands on Fri 16/10 (88 °F) and the lowest minimum on Thu 22/10 (47 °F). Forecast rain adds up to 0.63 in, roughly 94% of everything Altadena gets in an average October (0.67 in). The wettest day is Wed 21/10, with 0.57 in.
When is the wettest and the driest month in Altadena?
On the 25-year Meteorological and Solar Monthly & Annual Climatologies (January 2001 - December 2025) climatology, the wettest month in Altadena is February, at about 3.0 in, and the driest is June, at 0.04 in. The gap is 75 times: Altadena has a clearly separated wet season and dry season, so planning building work, travel or planting around the calendar genuinely pays. For October, the month you are reading this in, the average is 0.67 in.
What does the dew point say about how Altadena feels?
Right now in Altadena the air is at 71 °F with a dew point of 42 °F and relative humidity of 35%. The two are far apart, the signature of dry air: heat feels milder than the reading, but throat, eyes and skin dry out fast.
What is the climate of Altadena like through the year?
The warmest month in Altadena is August (75 °F on average) and the coldest is December (53 °F), a swing of about 12 °C around an annual mean of 63 °F. A swing of this size means a genuinely temperate climate: summer and winter call for different clothes, different housing and different habits.
Because Altadena lies in the northern hemisphere, at 34.19° north, summer falls in June, July and August, in the middle of the calendar.
How far is Altadena from Glendale?
The nearest large city to Altadena is Glendale, about 13 km away in a straight line, to the south-west, with 201,020 inhabitants. At that range the model hands both places virtually the same grid point, so the forecast for Altadena and the one for Glendale will almost always agree. Being larger, Glendale shows up in more searches, and plenty of people end up reading its forecast assuming it covers Altadena.
Words on this page
Apparent temperature
The temperature the body actually feels, rather than the one on the thermometer. It combines air temperature with wind, which carries heat away faster, and humidity, which slows the evaporation of sweat. That is why 30 °C in dry air with a breeze is easier than 28 °C in still, muggy air.
Dew point
The temperature air would have to cool to, at constant pressure and moisture, for water to start condensing. The closer the dew point sits to the air temperature, the less room the vapour has and the muggier the day feels.
Millimetre of rain
The depth of water rain would leave on a flat surface with no run-off. One millimetre is one litre per square metre, no matter how large the area measured is.
Standard definition by World Meteorological Organization (WMO) · Millimetre of rain
Climate normal
The average of a climate element — temperature, rainfall, humidity — computed over a long, standardised period, usually thirty years. It does not predict anything: it says what is typical for that place in that month, and gives you a ruler for calling a week warm or wet.
Standard definition by World Meteorological Organization (WMO) · Climate normal
Forecast model
A program that solves the equations of the atmosphere on a grid of points and steps forward in time from the state observed now. Your city forecast is the model value at the nearest grid point, which is why two neighbouring towns get almost the same numbers.
Standard definition by MET Norway (Meteorologisk institutt) · Forecast model
Model run
The time the model was executed with the latest observations. Every forecast belongs to a run, and runs age: one from six hours ago knows nothing about the shower that started afterwards. It is the first thing to check when two sources disagree.
Standard definition by MET Norway (Meteorologisk institutt) · Model run
Source, model and licence
- Model
- MET Norway, a partir do ECMWF HRES e, na área nórdica, do MEPS
- Model run
- 16/10/2026, 01:18 UTC
- Source
- MET Norway (Meteorologisk institutt) — Locationforecast 2.0 — Based on data from MET Norway. Licence: CC BY 4.0 / NLOD 2.0.
- Month-by-month climate
- NASA POWER — Climatology (MERRA-2, 2001–2020) — The data was obtained from National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project — Climatology API v2. Dados públicos da NASA, citação obrigatória.
- Cities, coordinates and population
- Dados de cidades: GeoNames (CC BY 4.0)
The page fetches fresh data every 30 minutes. Informational content. For severe weather warnings, follow your country’s official weather service and civil protection authority.