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Contents
- The climate of San Francisco
- The best time to visit San Francisco
- The worst time to visit San Francisco
- Spring weather in San Francisco
- Summer weather in San Francisco
- Autumn weather in San Francisco
- Winter weather in San Francisco
- 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
The climate of San Francisco
San Francisco, Costa Rica, resides in the unique weather envelope identified by the Köppen climate classification as an Am climate, known more commonly as a tropical monsoon. Situated on the isthmus connecting North and South America, this location experiences warm, humid conditions throughout the year.
A yearly review of the climate parameters reveals a noticeable consistency in San Francisco's temperature. High temps, fluctuating minimally from 25.4°C (77.7°F) to 29.7°C (85.5°F), maintain a relatively steady warmth throughout the year. Low temperatures show a similar pattern as they range from 16.8°C (62.2°F) to 19.8°C (67.6°F), creating an environment that rarely dips into cool territory. The relative humidity parallels the tropical nature of the region, remaining between 70% and 89% over the course of the year which manifests in misty mornings and occasional heavy air.
Rainfall in San Francisco embodies the monsoon characteristics of the location’s climate classification with the volume of rainfall transforming significantly throughout the year: it ranges from a modest 17mm (0.67") to a drenching 396mm (15.59"). The downpour reaches its peak in October with 30.2 days of rainfall. Similarly, San Francisco experiences a considerable degree in variability in daylight hours and sunshine duration, spanning from 11.6 to 12.7 hours of daylight and 7 to 9.4 hours of sunshine.
Despite the dramatic shifts in rainfall, sunshine, and daylight, other weather parameters maintain a rather stable arc throughout the year. The year-round visibility averages between 7km (4.3mi) and 10km (6.2mi) while the wind speed stays within 3.8km/h (2.4mph) to 10.6km/h (6.6mph).
A yearly review of the climate parameters reveals a noticeable consistency in San Francisco's temperature. High temps, fluctuating minimally from 25.4°C (77.7°F) to 29.7°C (85.5°F), maintain a relatively steady warmth throughout the year. Low temperatures show a similar pattern as they range from 16.8°C (62.2°F) to 19.8°C (67.6°F), creating an environment that rarely dips into cool territory. The relative humidity parallels the tropical nature of the region, remaining between 70% and 89% over the course of the year which manifests in misty mornings and occasional heavy air.
Rainfall in San Francisco embodies the monsoon characteristics of the location’s climate classification with the volume of rainfall transforming significantly throughout the year: it ranges from a modest 17mm (0.67") to a drenching 396mm (15.59"). The downpour reaches its peak in October with 30.2 days of rainfall. Similarly, San Francisco experiences a considerable degree in variability in daylight hours and sunshine duration, spanning from 11.6 to 12.7 hours of daylight and 7 to 9.4 hours of sunshine.
Despite the dramatic shifts in rainfall, sunshine, and daylight, other weather parameters maintain a rather stable arc throughout the year. The year-round visibility averages between 7km (4.3mi) and 10km (6.2mi) while the wind speed stays within 3.8km/h (2.4mph) to 10.6km/h (6.6mph).
The best time to visit San Francisco
The most pleasant time to visit San Francisco, Costa Rica, hinges on an individual's weather preferences. However, considering the average weather parameters, the best time would arguably be between December and March. During these months, the rainfall is modest, ranging from 17mm (0.67") to 21mm (0.83"), and the number of rainy days is less than other periods, allowing visitors to enjoy significantly more sunshine. Specifically, December offers up to 8.7 hours of sunshine, coupled with more daylight hours, hence allowing tourists ample time to indulge in outdoor activities.
The worst time to visit San Francisco
Taking into account the key climate parameters, the challenging period for traveling to San Francisco from a weather perspective is between May and November. The coastal city is hit by its heaviest rainfall within these months, as the downpour shoots up to an overwhelming 396mm (15.59") in October. There's also an increase in the number of rainy days during this spell, hitting a peak of 30.2 days in October, and reduced visibility due to cloud cover.
Spring weather in San Francisco
In San Francisco, spring spans from March to May. During this period, temperature highs elevate from a comfortable 27.3°C (81.1°F) in March to peaks around 29.7°C (85.5°F) in May, while the lows climb from 17.2°C (63°F) to 19.8°C (67.6°F). Additionally, the rainfall more than quadruples from 21mm (0.83") in March to a lofty 339mm (13.35") in May. This surge in precipitation is accompanied by increased cloud cover and declining sunshine hours, illustrating the transition from the dry to wet season.
Summer weather in San Francisco
The summer, from June to August, reveals consistent temperatures, securing highs between 26.3°C (79.3°F) and 26.7°C (80.1°F) and lows from 18.9°C (66°F) to 19.5°C (67.1°F). The rainfall tilts slightly from 323mm (12.72") in June to 287mm (11.3") in August while the relative humidity levels exceed 85%. The wind speed diminishes to around 4.5km/h (2.8mph) and 6km/h (3.7mph), further intensifying the warm summer feel in the air.
Autumn weather in San Francisco
Autumn months, extending from September to November, provide a respite from the summer’s scorching heat. Temperatures drop slightly and remain stable; highs fluctuate between 25.4°C (77.7°F) and 26.3°C (79.3°F) while the lows sway from 18.9°C (66°F) to 19.2°C (66.6°F). However, this period ushers in the city's highest rainfall volumes, with October witnessing rainfall of around 396mm (15.59").
Winter weather in San Francisco
In winter, from December through February, the climate in San Francisco is at its most pleasant. Temperature highs range from 26.5°C (79.7°F) to 28.3°C (82.9°F), while the lows remain steady from 16.8°C (62.2°F) to 17.2°C (63°F). Accompanying this is a marked reduction in rainfall and an increase in sunshine hours, resulting in a mild and enjoyable winter scenario ideal for outdoor exploration.
Weather in January
Starting the year, January in San Francisco, Costa Rica, offers a blend of moderate temperatures that encourage outdoor activities. Despite the seemingly perfect temperatures, it is important to carry a light jacket due to the cooler nights. Weather in January »
Weather in February
February ushers in a slight increase in temperatures compared to its predecessor. Reduced rainfall from January indicates the emergence of a drier season in San Francisco. The distinct trait of this month is the improved visibility that stands at 10km (6.2mi). Weather in February »
Weather in March
March denotes a transition into warmer weather, with a discernible increase in temperatures from February. Despite the warmer weather, rainfall slightly increases to 21mm (0.83"), reminding us that San Francisco still experiences scattered showers. Weather in March »
Weather in April
In April, San Francisco displays drastic changes in weather patterns, notably the vast increase in rainfall reaching up to 86mm (3.39"). Simultaneously, temperatures remain consistent with March's, denoting the contrast in this monthly transition. Weather in April »
Weather in May
May exhibits a substantial escalation in the depth of the wet season in San Francisco. From April, temperatures slightly drop, and a remarkable amount of rainfall sets in. This month is characterized by the highest recorded rainfall of 339mm (13.35"), effectively saturating the city. Weather in May »
Weather in June
Navigating into June, San Francisco continues to experience elevated levels of humidity and rainfall, a signature characteristic of Costa Rican weather. A slight drop in temperatures from May creates a mildly cooler environment. Alongside this, wind speeds decrease to 4.5km/h (2.8mph), allowing for calmer days amidst the rain-drenched city. Weather in June »
Weather in July
July, seemingly unaltered from June, maintains consistent rainfall and temperature levels. The minor increase in wind speed to 6km/h (3.7mph) might signal a shift in weather conditions in San Francisco. Interesting to note is the maintained UV index, an underlying reminder of Costa Rica's position near the Equator. Weather in July »
Weather in August
August denotes a similar weather pattern to July, with marginal changes in temperatures and rainfall. A dwindling visibility down to 7km (4.3mi) underscores the ongoing dominance of the rain over San Francisco. While the showers persist, the average hours of daylight begin to reduce, indicating the close of the long summer days. Weather in August »
Weather in September
Venturing into September, San Francisco's weather adjusts subtly, with temperatures and rainfall remaining comparatively unaltered from August. An intriguing trait of this month is the marked decrease in wind speed, dipping to 3.8km/h (2.4mph). Weather in September »
Weather in October
October signifies the peak of the wet season in San Francisco, with the highest recorded rainfall days of 30.2. Nonetheless, temperatures remain somewhat constant, reiterating the consistency in climatic conditions throughout the year. Weather in October »
Weather in November
November signals a progressive shift towards the year-end, with a noteworthy decrease in rainfall, down to 144mm (5.67"). However, the temperature and humidity levels stay relatively consistent with October. The unabated excitement over Sunshine hours finally gaining an upper hand over rain showers is palpable across San Francisco. Weather in November »
Weather in December
December rolls in by easing out of the rainy season, with the low rainfall recorded at 46mm (1.81"). Inhabitants of San Francisco can finally look forward to drier days and holiday festivities. Hallmarked by the strengthening of wind speed to 8.7km/h (5.4mph), it concludes the year with a significant meteorological change. Weather in December »
[Resources]Frequently asked questions
How much does it rain in San Francisco?
In San Francisco, Costa Rica, during the entire year, the rain falls for 272 days and collects up to 2217mm (87.28") of precipitation.
When is the highest UV index in San Francisco?
January through April, June, July, September, October and December, with an average maximum UV index of 6, are months with the highest UV index in San Francisco.
What is the driest month in San Francisco?
February is the month with the least rainfall. Rain falls for 10.3 days and accumulates 17mm (0.67") of precipitation.
What is the hottest time of year in San Francisco?
In San Francisco, March and April are characterised by the peak of temperatures, recording an average high of 29.7°C (85.5°F).
What is the least humid month in San Francisco?
The least humid month is March, with an average relative humidity of 70%.
What month has the most sunshine in San Francisco?
March has the most sunshine of the year in San Francisco, with an average of 9.4h of sunshine.
What is the month with the lowest UV index in San Francisco?
May, August and November, with an average maximum UV index of 5, are months with the lowest UV index in San Francisco.
When are the longest days in San Francisco?
The month with the longest days in San Francisco, Costa Rica, is June, with an average of 12h and 42min of daylight.
What month is the coldest in San Francisco?
The coldest temperatures occur during October, when averages reach a peak of 25.4°C (77.7°F) and a low of 18.9°C (66°F).
What is the most humid month in San Francisco?
With an average relative humidity of 89%, October is the most humid month in San Francisco, Costa Rica.
What is the rainiest month in San Francisco?
The month with the most rainfall in San Francisco, Costa Rica, is October, when the rain falls for 30.2 days and typically aggregates up to 396mm (15.59") of precipitation.
What is the month with the least sunshine in San Francisco?
October has the least sunshine of the year in San Francisco, Costa Rica, with an average of 7h of sunshine.
What is the month with the shortest days in San Francisco?
The month with the shortest days in San Francisco, Costa Rica, is December, with an average of 11h and 36min of daylight.
Is there Daylight Saving Time (DST) in San Francisco?
San Francisco does not observe Daylight Saving Time (DST). CST timezone is used throughout the entire year.
Average temperature
San Francisco, Costa Rica
The warmest months (with the highest average high temperature) are March and April (29.7°C).
The month with the lowest average high temperature is October (25.4°C).
The month with the highest average low temperature is May (19.8°C).
The coldest month (with the lowest average low temperature) is January (16.8°C).
Average pressure
San Francisco, Costa Rica
- Average pressure in January:
1012.1mbar - Average pressure in February:
1011.8mbar - Average pressure in March:
1011.9mbar - Average pressure in April:
1011.3mbar - Average pressure in May:
1011mbar - Average pressure in June:
1011mbar
- Average pressure in July:
1011.3mbar - Average pressure in August:
1011.2mbar - Average pressure in September:
1011mbar - Average pressure in October:
1010.7mbar - Average pressure in November:
1010.9mbar - Average pressure in December:
1011.5mbar
The month with the highest atmospheric pressure is January (1012.1mbar).
The month with the lowest atmospheric pressure is October (1010.7mbar).
Average wind speed
San Francisco, Costa Rica
- Average wind speed in January:
10.5km/h - Average wind speed in February:
10.6km/h - Average wind speed in March:
9.5km/h - Average wind speed in April:
6.6km/h - Average wind speed in May:
4.8km/h - Average wind speed in June:
4.5km/h
- Average wind speed in July:
6km/h - Average wind speed in August:
4.6km/h - Average wind speed in September:
3.8km/h - Average wind speed in October:
4.1km/h - Average wind speed in November:
6.2km/h - Average wind speed in December:
8.7km/h
The windiest month (with the highest average wind speed) is February (10.6km/h).
The calmest month (with the lowest average wind speed) is September (3.8km/h).
Average humidity
San Francisco, Costa Rica
The month with the highest relative humidity is October (89%).
The month with the lowest relative humidity is March (70%).
Average rainfall
San Francisco, Costa Rica
- Average rainfall in January:
21mm - Average rainfall in February:
17mm - Average rainfall in March:
21mm - Average rainfall in April:
86mm - Average rainfall in May:
339mm - Average rainfall in June:
323mm
- Average rainfall in July:
249mm - Average rainfall in August:
287mm - Average rainfall in September:
288mm - Average rainfall in October:
396mm - Average rainfall in November:
144mm - Average rainfall in December:
46mm
The wettest month (with the highest rainfall) is October (396mm).
The driest month (with the least rainfall) is February (17mm).
Average rainfall days
San Francisco, Costa Rica
- Average rainfall days in January:
11.3 days - Average rainfall days in February:
10.3 days - Average rainfall days in March:
14.5 days - Average rainfall days in April:
20 days - Average rainfall days in May:
27.2 days - Average rainfall days in June:
28 days
- Average rainfall days in July:
28.3 days - Average rainfall days in August:
27.6 days - Average rainfall days in September:
29.4 days - Average rainfall days in October:
30.2 days - Average rainfall days in November:
26.9 days - Average rainfall days in December:
18.3 days
The month with the highest number of rainy days is October (30.2 days).
The month with the least rainy days is February (10.3 days).
Average daylight / Average sunshine
San Francisco, Costa Rica
- Average daylight in January:
11h and 4min - Average daylight in February:
11h and 5min - Average daylight in March:
12h and 1min - Average daylight in April:
12h and 2min - Average daylight in May:
12h and 4min - Average daylight in June:
12h and 4min
- Average daylight in July:
12h and 4min - Average daylight in August:
12h and 2min - Average daylight in September:
12h and 1min - Average daylight in October:
11h and 5min - Average daylight in November:
11h and 4min - Average daylight in December:
11h and 4min
The month with the longest days is June (Average daylight: 12h and 42min).
The month with the shortest days is December (Average daylight: 11h and 36min).
- Average sunshine in January:
8h and 2min - Average sunshine in February:
9h and 1min - Average sunshine in March:
9h and 2min - Average sunshine in April:
9h and 1min - Average sunshine in May:
7h and 5min - Average sunshine in June:
7h and 5min
- Average sunshine in July:
8h and 4min - Average sunshine in August:
7h and 5min - Average sunshine in September:
7h and 4min - Average sunshine in October:
7h and 0min - Average sunshine in November:
7h and 3min - Average sunshine in December:
8h and 4min
The month with the most sunshine is March (Average sunshine: 9h and 24min).
The month with the least sunshine is October (Average sunshine: 7h and 0min).
Average sunshine days
San Francisco, Costa Rica
- Average sunshine days in January:
16.7 days - Average sunshine days in February:
15 days - Average sunshine days in March:
14.6 days - Average sunshine days in April:
8.2 days - Average sunshine days in May:
2.8 days - Average sunshine days in June:
1.7 days
- Average sunshine days in July:
2.2 days - Average sunshine days in August:
2.8 days - Average sunshine days in September:
0.5 days - Average sunshine days in October:
0.6 days - Average sunshine days in November:
2.4 days - Average sunshine days in December:
10.1 days
The month with the most sunshine days is January (16.7 days).
The month with the least sunshine days is September (0.5 days).
Average UV index
San Francisco, Costa Rica
The months with the highest UV index are January, February, March, April, June, July, September, October and December (UV index 6).
The months with the lowest UV index are May, August and November (UV index 5).
Average cloud cover
San Francisco, Costa Rica
The month with the most cloud cover is October (Cloud cover 54).
The month with the least cloud cover is February (Cloud cover 19).
Average visibility
San Francisco, Costa Rica
The months with the highest visibility are February and March (10km).
The months with the lowest visibility are August, September, October and November (7km).
San Francisco, Costa Rica
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