April weather forecastAltadena, CA
April
Weather in April
April is a pleasant spring month in Altadena, California, with an average temperature varying between 70°F (21.1°C) and 49.8°F (9.9°C).Temperature
During April, Altadena records an average high-temperature of an agreeable 70°F (21.1°C), marking a slight divergence from March's 66°F (18.9°C). April witnesses an average nighttime temperature of 49.8°F (9.9°C).Humidity
The average relative humidity in April is 54%.Rainfall
In Altadena, during April, the rain falls for 5.8 days and regularly aggregates up to 0.63" (16mm) of precipitation. Throughout the year, there are 52 rainfall days, and 8.82" (224mm) of precipitation is accumulated.Daylight
In April, the average length of the day is 13h and 4min.On the first day of April in Altadena, sunrise is at 6:38 am and sunset at 7:13 pm. On the last day of the month, sunrise is at 6:03 am and sunset at 7:36 pm PDT.
Sunshine
In Altadena, the average sunshine in April is 11.4h.UV index
In April, the average daily maximum UV index is 5. A UV Index estimate of 3 to 5 represents a moderate threat to health from unsafe exposure to UV radiation for average individuals.Note: In April, the maximum UV index of 5 translates into these guidelines:
Undertake protective steps - Preventing sun damage is advised. The Sun is most powerful around mid-day, so it's a good practice to reduce direct exposure. For holistic sun protection encompassing the eyes, ears, face, and neck, a wide-brim hat is key.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in April
Altadena, CA
- Average high temperature in April: 70°F
The warmest month (with the highest average high temperature) is August (86.2°F).
The month with the lowest average high temperature is December (61°F).
- Average low temperature in April: 49.8°F
The month with the highest average low temperature is August (64.4°F).
The coldest month (with the lowest average low temperature) is December (45.5°F).
Average pressure in April
Altadena, CA
- Average pressure in April: 29.96"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).
Average wind speed in April
Altadena, CA
- Average wind speed in April: 5.8mph
The windiest month (with the highest average wind speed) is April (5.8mph).
The calmest month (with the lowest average wind speed) is September (4.4mph).
Average humidity in April
Altadena, CA
- Average humidity in April: 54%
The months with the highest relative humidity are March, May and June (56%).
The month with the lowest relative humidity is November (46%).
Average rainfall in April
Altadena, CA
- Average rainfall in April: 0.63"
The wettest month (with the highest rainfall) is February (1.81").
The driest month (with the least rainfall) is June (0.04").
Average rainfall days in April
Altadena, CA
- Average rainfall days in April: 5.8 days
The month with the highest number of rainy days is March (7.5 days).
The month with the least rainy days is June (1.3 days).
Average daylight in April /
Average sunshine in April
Altadena, CA
- Average daylight in April: 13h and 6min
The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).
- Average sunshine in April: 11h and 24min
The months with the most sunshine are June and July (Average sunshine: 12h and 6min).
The months with the least sunshine are February and December (Average sunshine: 6h and 54min).
Average sunshine days in April
Altadena, CA
- Average sunshine days in April: 23.1 days
The month with the most sunshine days is June (27.2 days).
The month with the least sunshine days is February (21.3 days).
Average UV index in April
Altadena, CA
- Average UV index in April: 5
The months with the highest UV index are June, July, August and September (UV index 6).
The month with the lowest UV index is December (UV index 3).
Average cloud cover in April
Altadena, CA
- Average cloud cover in April: 16
The month with the most cloud cover is March (Cloud cover 22).
The month with the least cloud cover is August (Cloud cover 5).
Average visibility in April
Altadena, CA
- Average visibility in April: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
