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Contents
- Weather in January
- Weather in February
- Weather in March
- Weather in April
- Weather in May
- Weather in June
- Weather in July
- Weather in August
- Weather in September
- Weather in October
- Weather in November
- Weather in December
- Frequently asked questions
- Average temperature
- Average pressure
- Average wind speed
- Average humidity
- Average rainfall
- Average rainfall days
- Average daylight
- Average sunshine
- Average sunshine days
- Average UV index
- Average cloud cover
- Average visibility
Weather in January
January, the same as December, in Port Costa, California, is a moderate winter month, with an average temperature ranging between max 56.5°F (13.6°C) and min 43°F (6.1°C). With the advent of January, Port Costa's high-temperatures adjust to a still refreshing 56.5°F (13.6°C), closely aligning with the preceding month. Weather in January »
Weather in February
February, the last month of the winter in Port Costa, is another refreshing month, with an average temperature varying between 59.2°F (15.1°C) and 44.1°F (6.7°C). February's beginning signals an average high-temperature of a still mild 59.2°F (15.1°C), barely different from January's 56.5°F (13.6°C). Weather in February »
Weather in March
The first month of the spring, March, is a comfortable month in Port Costa, California, with an average temperature fluctuating between 61.5°F (16.4°C) and 45°F (7.2°C). The introduction of March sees an average high-temperature of an enjoyable 61.5°F (16.4°C), hardly deviating from February. Weather in March »
Weather in April
April, the same as March, is another comfortable spring month in Port Costa, California, with temperature in the range of an average high of 66.7°F (19.3°C) and an average low of 46.8°F (8.2°C). Port Costa experiences a minor change to a still refreshing 66.7°F (19.3°C) in average high-temperature during April, closely reflecting March. Weather in April »
Weather in May
May, the last month of the spring in Port Costa, is a pleasant month, with an average temperature varying between 71.1°F (21.7°C) and 49.8°F (9.9°C). Port Costa's weather, upon May's arrival, documents an average high-temperature of an agreeable 71.1°F (21.7°C), nearly identical to the prior month. Weather in May »
Weather in June
The first month of the summer, June, is a warm month in Port Costa, California, with temperature in the range of an average high of 77.7°F (25.4°C) and an average low of 54.1°F (12.3°C). June's onset brings a subtle temperature rise, moving from an agreeable 71.1°F (21.7°C) in May to a warm 77.7°F (25.4°C). Weather in June »
Weather in July
July, the same as June, is another warm summer month in Port Costa, California, with an average temperature ranging between min 55.4°F (13°C) and max 80.1°F (26.7°C). In Port Costa, the months of July and September register the highest average temperatures, peaking at 80.1°F (26.7°C). Weather in July »
Weather in August
August, the last month of the summer in Port Costa, is another warm month, with an average temperature fluctuating between 79.7°F (26.5°C) and 56.5°F (13.6°C). As August takes its course, Port Costa's average high-temperature registers at a still moderately hot 79.7°F (26.5°C), closely aligning with the preceding month. Weather in August »
Weather in September
The first month of the autumn, September, is also a moderately hot month in Port Costa, California, with an average temperature fluctuating between 56.3°F (13.5°C) and 80.1°F (26.7°C). The highest point of temperatures falls in July and September, when the average high-temperature ascends to 80.1°F (26.7°C). Weather in September »
Weather in October
October, like September, is an agreeable autumn month in Port Costa, California, with an average temperature varying between 72.9°F (22.7°C) and 54°F (12.2°C). As October arrives, Port Costa's weather displays a minor decrease in high-temperatures, transitioning from September's warm 80.1°F (26.7°C) to a pleasant 72.9°F (22.7°C). Weather in October »
Weather in November
The last month of the autumn, November, is another refreshing month in Port Costa, California, with an average temperature ranging between max 63°F (17.2°C) and min 47.7°F (8.7°C). A shift in Port Costa's weather is observed as October turns into November, with the average high temperature reducing from a pleasant 72.9°F (22.7°C) to an enjoyable 63°F (17.2°C). Weather in November »
Weather in December
The first month of the winter, December, is still a refreshing month in Port Costa, California, with an average temperature fluctuating between 55.4°F (13°C) and 43.2°F (6.2°C). December, having an average high-temperature of 55.4°F (13°C) and an average low-temperature of 43.2°F (6.2°C), is the coldest month. Weather in December »
Updated: Aug 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How many days does it rain?
In Port Costa, during the entire year, the rain falls for 56.9 days and collects up to 4.88" (124mm) of precipitation.
When is the lowest UV index in Port Costa?
January, February, November and December, with an average maximum UV index of 3, are months with the lowest UV index.
What is the wettest month?
The month with the most rainfall in Port Costa is February, when the rain falls for 6.8 days and typically aggregates up to 1.14" (29mm) of precipitation.
What is the most humid month?
With an average relative humidity of 75%, March is the most humid month.
When is Daylight Saving Time (DST)?
On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from PST to PDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from PDT to PST.
When are the longest days?
June has the longest days of the year, with an average of 14h and 48min of daylight.
When is the highest UV index?
The month with the highest UV index is June, with an average maximum UV index of 6.
What time of the year is the hottest?
July and September, with an average high-temperature of 80.1°F (26.7°C), are warmest months in Port Costa.
What is the driest month?
July and August are months with the least rain when the rain falls for 1.5 days and typically aggregates up to 0.04" (1mm) of rain.
What month has the most sunshine?
July has the most sunshine of the year, with an average of 12h of sunshine.
What are the least humid months?
September and October, with an average relative humidity of 60%, are the least humid months.
What is the coldest time of year?
December is the month when Port Costa sees the average lowest temperatures, with a high of 55.4°F (13°C) and a low of 43.2°F (6.2°C).
What is the month with the shortest days in Port Costa?
The month with the shortest days is December, with an average of 9h and 36min of daylight.
What is the month with the least sunshine?
December has the least sunshine of the year, with an average of 5.7h of sunshine.
Average temperature
Port Costa, CA
The warmest months (with the highest average high temperature) are July and September (80.1°F).
The month with the lowest average high temperature is December (55.4°F).
The month with the highest average low temperature is August (56.5°F).
The coldest month (with the lowest average low temperature) is January (43°F).
Average pressure
Port Costa, CA
- Average pressure in January:
30.14"Hg - Average pressure in February:
30.08"Hg - Average pressure in March:
30.07"Hg - Average pressure in April:
30.03"Hg - Average pressure in May:
29.97"Hg - Average pressure in June:
29.91"Hg
- Average pressure in July:
29.93"Hg - Average pressure in August:
29.92"Hg - Average pressure in September:
29.92"Hg - Average pressure in October:
29.98"Hg - Average pressure in November:
30.07"Hg - Average pressure in December:
30.11"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed
Port Costa, CA
- Average wind speed in January:
4.9mph - Average wind speed in February:
5.7mph - Average wind speed in March:
6mph - Average wind speed in April:
6.5mph - Average wind speed in May:
7.1mph - Average wind speed in June:
6.9mph
- Average wind speed in July:
6.6mph - Average wind speed in August:
6.2mph - Average wind speed in September:
5.5mph - Average wind speed in October:
5mph - Average wind speed in November:
4.6mph - Average wind speed in December:
5.2mph
The windiest month (with the highest average wind speed) is May (7.1mph).
The calmest month (with the lowest average wind speed) is November (4.6mph).
Average humidity
Port Costa, CA
The month with the highest relative humidity is March (75%).
The months with the lowest relative humidity are September and October (60%).
Average rainfall
Port Costa, CA
- Average rainfall in January:
0.83" - Average rainfall in February:
1.14" - Average rainfall in March:
0.75" - Average rainfall in April:
0.2" - Average rainfall in May:
0.28" - Average rainfall in June:
0.08"
- Average rainfall in July:
0.04" - Average rainfall in August:
0.04" - Average rainfall in September:
0.08" - Average rainfall in October:
0.2" - Average rainfall in November:
0.47" - Average rainfall in December:
0.79"
The wettest month (with the highest rainfall) is February (1.14").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days
Port Costa, CA
- Average rainfall days in January:
7.7 days - Average rainfall days in February:
6.8 days - Average rainfall days in March:
10.2 days - Average rainfall days in April:
5.8 days - Average rainfall days in May:
3.6 days - Average rainfall days in June:
1.1 days
- Average rainfall days in July:
1.5 days - Average rainfall days in August:
0.9 days - Average rainfall days in September:
2.1 days - Average rainfall days in October:
3.4 days - Average rainfall days in November:
5.3 days - Average rainfall days in December:
8.5 days
The month with the highest number of rainy days is March (10.2 days).
The month with the least rainy days is August (0.9 days).
Average daylight / Average sunshine
Port Costa, CA
- Average daylight in January:
9h and 5min - Average daylight in February:
10h and 5min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 1min - Average daylight in May:
14h and 1min - Average daylight in June:
14h and 5min
- Average daylight in July:
14h and 3min - Average daylight in August:
13h and 4min - Average daylight in September:
12h and 2min - Average daylight in October:
11h and 1min - Average daylight in November:
10h and 1min - Average daylight in December:
9h and 4min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in January:
5h and 5min - Average sunshine in February:
6h and 1min - Average sunshine in March:
7h and 4min - Average sunshine in April:
10h and 2min - Average sunshine in May:
10h and 5min - Average sunshine in June:
11h and 4min
- Average sunshine in July:
12h and 0min - Average sunshine in August:
11h and 5min - Average sunshine in September:
11h and 1min - Average sunshine in October:
7h and 0min - Average sunshine in November:
6h and 3min - Average sunshine in December:
5h and 4min
The month with the most sunshine is July (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 42min).
Average sunshine days
Port Costa, CA
- Average sunshine days in January:
21.8 days - Average sunshine days in February:
20.1 days - Average sunshine days in March:
18.8 days - Average sunshine days in April:
22.8 days - Average sunshine days in May:
24.3 days - Average sunshine days in June:
26.7 days
- Average sunshine days in July:
27.2 days - Average sunshine days in August:
25.8 days - Average sunshine days in September:
26 days - Average sunshine days in October:
25.5 days - Average sunshine days in November:
23.6 days - Average sunshine days in December:
20.8 days
The month with the most sunshine days is July (27.2 days).
The month with the least sunshine days is March (18.8 days).
Average UV index
Port Costa, CA
The month with the highest UV index is June (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover
Port Costa, CA
The month with the most cloud cover is March (Cloud cover 37).
The month with the least cloud cover is July (Cloud cover 9).
Average visibility
Port Costa, CA
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).
Port Costa, California, USA
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