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Contents
- The climate of San Isidro
- The best time to visit San Isidro
- The worst time to visit San Isidro
- Spring weather in San Isidro
- Summer weather in San Isidro
- Autumn weather in San Isidro
- Winter weather in San Isidro
- 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 Isidro
San Isidro, Costa Rica experiences a tropical monsoon climate, which is classified as 'Am' in the Köppen climate system. The city's geographical position near the equator assures year-round warm weather and heavy seasonal rainfall, characteristic of a monsoon climate. Up to 438mm (17.24") of rainfall can be expected during the wettest months, between April and November, with the highest volumes occurring in October. The seasonality of rainfall sees a significant decrease from December to March, with monthly averages dropping to as low as 26mm (1.02") in February.
The city enjoys a stable temperature range across the year, with monthly average high temperatures hovering between 23°C (73.4°F) to 26°C (78.8°F). The lows dip slightly to a range of 13.8°C (56.8°F) to 17°C (62.6°F), preserving the tropical warmth. However, relative humidity levels can rise as high as 91% during the peak rainy months, adding a damp feel to the air.
The city has an average daylight hour count of 12 hours throughout the year and an average sunshine hour count that varies from 5.8 hours to 9.2 hours. These sunlight hours are widely spread over the year, contributing to the overall pleasant climate. Yet, higher cloud cover during rainy months can sometimes hamper this tropical sunshine.
The city enjoys a stable temperature range across the year, with monthly average high temperatures hovering between 23°C (73.4°F) to 26°C (78.8°F). The lows dip slightly to a range of 13.8°C (56.8°F) to 17°C (62.6°F), preserving the tropical warmth. However, relative humidity levels can rise as high as 91% during the peak rainy months, adding a damp feel to the air.
The city has an average daylight hour count of 12 hours throughout the year and an average sunshine hour count that varies from 5.8 hours to 9.2 hours. These sunlight hours are widely spread over the year, contributing to the overall pleasant climate. Yet, higher cloud cover during rainy months can sometimes hamper this tropical sunshine.
The best time to visit San Isidro
With warm temperatures persisting year-round, the best time to visit San Isidro depends largely on the traveler’s preference for rain. The period from February to April stands out as an optimum time to visit for those who prefers dry conditions. During this period, San Isidro receives much less rainfall, with levels averaging just 32mm (1.26") to 100mm (3.94"). Furthermore, the daily temperatures remain comfortably warm, ranging from 23.9°C (75°F) to 26°C (78.8°F).
The worst time to visit San Isidro
The least favorable time for travel to San Isidro, particularly for those who are not fond of heavy rainfall, would be the wet season, particularly from May to November. Rainfall during these months average from 301mm (11.85") to 438mm (17.24"). In addition, the increased relative humidity which reaches up to 91% might make the warm temperature feel hotter and more uncomfortable.
Spring weather in San Isidro
During the spring months of March to May, San Isidro experiences a shift from the dry period toward a more monsoonal climate. Average temperatures remain relatively stable from 24.3°C (75.7°F) to 26°C (78.8°F). While the month of March remains quite dry with just 28mm (1.1") of rain, the situation changes tendency in April and May, where rainfall averages jump to 100mm (3.94") and 369mm (14.53"), respectively.
Summer weather in San Isidro
Despite classified as summer months, June to August in San Isidro are part of the rainy season. Rainfall further intensifies, averaging between 301mm (11.85") and 378mm (14.88"). Daily temperatures persistently stay between 23°C (73.4°F) to 23.3°C (73.9°F). Relative humidity reaches as high as 90%, creating a muggy environment.
Autumn weather in San Isidro
During the autumn months of September to November, rainfall remains high. Considering the monsoon nature of San Isidro’s climate, rainfall averages from 344mm (13.54") to 438mm (17.24"). The monthly average temperature varies from 22.4°C (72.3°F) to 23°C (73.4°F), making it slightly cooler compared to the rest of the year.
Winter weather in San Isidro
In winter, from December through February, the weather significantly dries out. Rainfall reduces to between 26mm (1.02") to 65mm (2.56") monthly, making it an ideal time to enjoy outdoor activities. Meanwhile, daily temperatures remain comfortably warm, averaging between 23.4°C (74.1°F) to 25°C (77°F). This period also sees a slight decrease in humidity providing a comfortable winter getaway.
Weather in January
January is the starting point for the year, and notably so does its weather in San Isidro, Costa Rica. In a vibrant show of nature's dynamism, the temperature swings from a pleasant 13.8°C (56.8°F) to a warmer 23.9°C (75°F). Weather in January »
Weather in February
As we roll into February, San Isidro experiences an uptick in the mercury to 25°C (77°F), a slight but notable contrast to January's peak of 23.9°C (75°F). The weather remains somewhat consistent with the previous month, speaking in terms of relative humidity, daylight hours, and average wind speed. Weather in February »
Weather in March
March welcomes a surge in the minimum temperatures, with the thermostat fluctuating between 14.5°C (58.1°F) to 25.8°C (78.4°F). This increase in the minimum temperature is a characteristic trait of March when compared to the cooler lows of January and February. Weather in March »
Weather in April
April, a time of year when the weather gears up for some significant changes. The temperature spectrum widens from 15.9°C (60.6°F) to 26°C (78.8°F), signaling the arrival of warmer days and nights. However, the rainfall takes a steep rise this month, drenching the city more frequently than previous months. Weather in April »
Weather in May
As the calendar progresses to May, San Isidro embraces the full force of the rainy season with a significant spike in rainfall indices. The shift in the climate game is quite evident this month, with wind speeds dropping to the year's lowest level of 5.1km/h (3.2mph). Weather in May »
Weather in June
June calls for a careful look at the weather trends in San Isidro, Costa Rica. The temperatures stabilize, with a slight dip in the maximum average temperature to 23.3°C (73.9°F). An interesting fact about this season is the high humidity, with a relative value of 90%, indicating that the atmosphere is heavy with moisture. Weather in June »
Weather in July
The July climate scenario in San Isidro embraces the continuance of the rainy season. The maximum temperature consistently anchors at 23.3°C (73.9°F), same as what June experienced. The propensity for rainfall persists, although not as excessive as the previous two months. Weather in July »
Weather in August
San Isidro's August weather continues the rhythm set by July, with no change in the maximum temperature. This consistency in atmospheric conditions do mimic the previous month and foretells the near future. However, a crucial point to note is the slight increase in wind speed to 5.5km/h (3.4mph). Weather in August »
Weather in September
September marks a shift in the climatological patterns of San Isidro, manifesting a slight dip in the temperature spectrum to 16.4°C (61.5°F) - 23°C (73.4°F). Not bypassing the rainy season, this month's peak rainfall pushes the scale to 344mm (13.54"), a noticeable rise from August's 339mm (13.35"). Weather in September »
Weather in October
October stands testament to the transition from the glorious rainy season towards drier days. Intensive showers reaching a peak of 438mm (17.24") characterizes the climatological scene in San Isidro, unequivocally crowning it as the rainiest month of the year. Weather in October »
Weather in November
As November approaches, the weather in San Isidro begins noticeably shifting. With a significant decrease in rainfall at 165mm (6.5"), it is clear that the end of the rainy season is in sight. The variations in wind speeds, visibility, and other weather indicators do not hold much significance. Weather in November »
Weather in December
With December comes the much-awaited respite from perpetual rains and high levels of humidity in San Isidro. A considerable decline in rainfall to 65mm (2.56") and a relatable drop in relative humidity to 84% mark the end of the rainy season, opening up the dry season. Weather in December »
Updated: Jan 26, 2024
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How many days does it rain in San Isidro?
In San Isidro, Costa Rica, during the entire year, the rain falls for 287.8 days and collects up to 2585mm (101.77") of precipitation.
What are the months with the highest UV index in San Isidro?
January through December, with an average maximum UV index of 5, are months with the highest UV index in San Isidro.
When is the lowest UV index in San Isidro?
The months with the lowest UV index in San Isidro are January through December, with an average maximum UV index of 5.
What are the least humid months in San Isidro?
The months with the lowest humidity in San Isidro are February and March, with an average relative humidity of 75%.
What is the driest month in San Isidro?
February is the month with the least rainfall. Rain falls for 12.2 days and accumulates 26mm (1.02") of precipitation.
What month has the most sunshine in San Isidro?
February has the most sunshine of the year, with an average of 9.2h of sunshine.
What time of the year is the hottest in San Isidro?
April, recognised by an average high temperature of 26°C (78.8°F) and a low of 15.9°C (60.6°F), is San Isidro's warmest month.
When are the longest days in San Isidro?
With an average of 12h and 42min of daylight, June has the longest days of the year.
What are the most humid months in San Isidro?
September and October, with an average relative humidity of 91%, are most humid months in San Isidro.
What month is the coldest in San Isidro?
October stands out as San Isidro's coldest month, with temperatures ranging between an average high of 22.4°C (72.3°F) and a low of 16.1°C (61°F).
What is the rainiest month in San Isidro?
October is the month with the most rainfall in San Isidro, Costa Rica. Rain falls for 30.5 days and accumulates 438mm (17.24") of precipitation.
What is the month with the least sunshine in San Isidro?
The month with the least sunshine is October, with an average of 5.8h of sunshine.
What is the month with the shortest days in San Isidro?
The month with the shortest days in San Isidro is December, with an average of 11h and 36min of daylight.
Is there Daylight Saving Time (DST) in San Isidro?
San Isidro does not utilize Daylight Saving Time (DST). CST timezone is used over the entire year.
Average temperature
San Isidro, Costa Rica
The warmest month (with the highest average high temperature) is April (26°C).
The month with the lowest average high temperature is October (22.4°C).
The month with the highest average low temperature is June (17°C).
The coldest month (with the lowest average low temperature) is January (13.8°C).
Average pressure
San Isidro, Costa Rica
- Average pressure in January:
1012.3mbar - Average pressure in February:
1012mbar - Average pressure in March:
1012.1mbar - Average pressure in April:
1011.5mbar - Average pressure in May:
1011.2mbar - Average pressure in June:
1011.2mbar
- Average pressure in July:
1011.5mbar - Average pressure in August:
1011.3mbar - Average pressure in September:
1011.1mbar - Average pressure in October:
1010.8mbar - Average pressure in November:
1011.1mbar - Average pressure in December:
1011.7mbar
The month with the highest atmospheric pressure is January (1012.3mbar).
The month with the lowest atmospheric pressure is October (1010.8mbar).
Average wind speed
San Isidro, Costa Rica
- Average wind speed in January:
10.5km/h - Average wind speed in February:
10.7km/h - Average wind speed in March:
9.6km/h - Average wind speed in April:
7km/h - Average wind speed in May:
5.1km/h - Average wind speed in June:
5km/h
- Average wind speed in July:
6.8km/h - Average wind speed in August:
5.5km/h - Average wind speed in September:
4.3km/h - Average wind speed in October:
4.4km/h - Average wind speed in November:
6.5km/h - Average wind speed in December:
9km/h
The windiest month (with the highest average wind speed) is February (10.7km/h).
The calmest month (with the lowest average wind speed) is September (4.3km/h).
Average humidity
San Isidro, Costa Rica
The months with the highest relative humidity are September and October (91%).
The months with the lowest relative humidity are February and March (75%).
Average rainfall
San Isidro, Costa Rica
- Average rainfall in January:
32mm - Average rainfall in February:
26mm - Average rainfall in March:
28mm - Average rainfall in April:
100mm - Average rainfall in May:
369mm - Average rainfall in June:
378mm
- Average rainfall in July:
301mm - Average rainfall in August:
339mm - Average rainfall in September:
344mm - Average rainfall in October:
438mm - Average rainfall in November:
165mm - Average rainfall in December:
65mm
The wettest month (with the highest rainfall) is October (438mm).
The driest month (with the least rainfall) is February (26mm).
Average rainfall days
San Isidro, Costa Rica
- Average rainfall days in January:
14.3 days - Average rainfall days in February:
12.2 days - Average rainfall days in March:
15.5 days - Average rainfall days in April:
21.9 days - Average rainfall days in May:
28.7 days - Average rainfall days in June:
28.9 days
- Average rainfall days in July:
29.7 days - Average rainfall days in August:
29.2 days - Average rainfall days in September:
29.5 days - Average rainfall days in October:
30.5 days - Average rainfall days in November:
27.9 days - Average rainfall days in December:
19.5 days
The month with the highest number of rainy days is October (30.5 days).
The month with the least rainy days is February (12.2 days).
Average daylight / Average sunshine
San Isidro, 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 5min - Average sunshine in February:
9h and 1min - Average sunshine in March:
8h and 5min - Average sunshine in April:
8h and 4min - Average sunshine in May:
6h and 5min - Average sunshine in June:
6h and 1min
- Average sunshine in July:
7h and 1min - Average sunshine in August:
6h and 4min - Average sunshine in September:
6h and 3min - Average sunshine in October:
5h and 5min - Average sunshine in November:
6h and 2min - Average sunshine in December:
7h and 5min
The month with the most sunshine is February (Average sunshine: 9h and 12min).
The month with the least sunshine is October (Average sunshine: 5h and 48min).
Average sunshine days
San Isidro, Costa Rica
- Average sunshine days in January:
13.1 days - Average sunshine days in February:
12.7 days - Average sunshine days in March:
13.5 days - Average sunshine days in April:
6.4 days - Average sunshine days in May:
1.8 days - Average sunshine days in June:
0.5 days
- Average sunshine days in July:
0.7 days - Average sunshine days in August:
0.7 days - Average sunshine days in September:
0.1 days - Average sunshine days in October:
0.4 days - Average sunshine days in November:
1.6 days - Average sunshine days in December:
9.1 days
The month with the most sunshine days is March (13.5 days).
The month with the least sunshine days is September (0.1 days).
Average UV index
San Isidro, Costa Rica
The months with the highest UV index are January, February, March, April, May, June, July, August, September, October, November and December (UV index 5).
The months with the lowest UV index are January, February, March, April, May, June, July, August, September, October, November and December (UV index 5).
Average cloud cover
San Isidro, Costa Rica
The month with the most cloud cover is October (Cloud cover 68).
The month with the least cloud cover is February (Cloud cover 30).
Average visibility
San Isidro, Costa Rica
The months with the highest visibility are January, February and March (9km).
The months with the lowest visibility are August, September, October and November (6km).
San Isidro, Costa Rica
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