Average Weather in Surabaya Indonesia
In Surabaya, the wet season is overcast, the dry season is partly cloudy, and it is hot and oppressive year round. Over the course of the year, the temperature typically varies from 75°F to 93°F and is rarely below 71°F or above 96°F.
Based on the beach/pool score, the best time of year to visit Surabaya for hot-weather activities is from mid June to late September.
The temperature in Surabaya varies so little throughout the year that it is not entirely meaningful to discuss hot and cold seasons.
Average High and Low Temperature
The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.
Average Hourly Temperature
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
In Surabaya, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.
The clearer part of the year in Surabaya begins around May 5 and lasts for 5.2 months, ending around October 13. On August 5, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 48% of the time, and overcast or mostly cloudy 52% of the time.
The cloudier part of the year begins around October 13 and lasts for 6.8 months, ending around May 5. On January 22, the cloudiest day of the year, the sky is overcast or mostly cloudy 91% of the time, and clear, mostly clear, or partly cloudy 9% of the time.
Cloud Cover Categories
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Surabaya varies very significantly throughout the year.
The wetter season lasts 5.5 months, from November 14 to April 30, with a greater than 37% chance of a given day being a wet day. The chance of a wet day peaks at 70% on February 1.
The drier season lasts 6.5 months, from April 30 to November 14. The smallest chance of a wet day is 3% on August 18.
Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 70% on February 1.
Daily Chance of Precipitation
To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. Surabaya experiences extreme seasonal variation in monthly rainfall.
The rainy period of the year lasts for 11 months, from September 12 to August 3, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around January 26, with an average total accumulation of 11.1 inches.
The rainless period of the year lasts for 1.3 months, from August 3 to September 12. The least rain falls around August 24, with an average total accumulation of 0.3 inches.
Average Monthly Rainfall
The length of the day in Surabaya does not vary substantially over the course of the year, staying within 32 minutes of 12 hours throughout. In 2019, the shortest day is June 21, with 11 hours, 42 minutes of daylight; the longest day is December 22, with 12 hours, 33 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:00 AM on November 14, and the latest sunrise is 43 minutes later at 5:42 AM on July 16. The earliest sunset is at 5:18 PM on May 25, and the latest sunset is 37 minutes later at 5:55 PM on January 30.
Daylight saving time (DST) is not observed in Surabaya during 2019.
Sunrise & Sunset with Twilight
We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.
The perceived humidity level in Surabaya, as measured by the percentage of time in which the humidity comfort level is muggy, oppressive, or miserable, does not vary significantly over the course of the year, staying within 4% of 96% throughout.
Humidity Comfort Levels
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.
The average hourly wind speed in Surabaya experiences significant seasonal variation over the course of the year.
The windier part of the year lasts for 4.6 months, from May 27 to October 15, with average wind speeds of more than 7.0 miles per hour. The windiest day of the year is August 10, with an average hourly wind speed of 8.8 miles per hour.
The calmer time of year lasts for 7.4 months, from October 15 to May 27. The calmest day of the year is April 2, with an average hourly wind speed of 5.1 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in Surabaya varies throughout the year.
The wind is most often from the east for 8.0 months, from March 25 to November 24, with a peak percentage of 75% on May 14. The wind is most often from the west for 4.0 months, from November 24 to March 25, with a peak percentage of 67% on January 1.
Surabaya is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.
The average water temperature does not vary significantly over the course of the year, remaining within 2°F of 84°F throughout.
Average Water Temperature
Best Time of Year to Visit
To characterize how pleasant the weather is in Surabaya throughout the year, we compute two travel scores.
The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best time of year to visit Surabaya for general outdoor tourist activities is from early July to early September, with a peak score in the second week of August.
The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Surabaya for hot-weather activities is from mid June to late September, with a peak score in the first week of August.
For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.
Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.
Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.
Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.
Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.
Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).
Temperatures in Surabaya are sufficiently warm year round that it is not entirely meaningful to discuss the growing season in these terms. We nevertheless include the chart below as an illustration of the distribution of temperatures experienced throughout the year.
Time Spent in Various Temperature Bands and the Growing Season
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.
Growing Degree Days
This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.
The average daily incident shortwave solar energy experiences some seasonal variation over the course of the year.
The brighter period of the year lasts for 2.3 months, from August 12 to October 21, with an average daily incident shortwave energy per square meter above 6.4 kWh. The brightest day of the year is September 22, with an average of 6.9 kWh.
The darker period of the year lasts for 3.9 months, from November 26 to March 23, with an average daily incident shortwave energy per square meter below 4.8 kWh. The darkest day of the year is January 20, with an average of 4.2 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Surabaya are -7.249 deg latitude, 112.751 deg longitude, and 16 ft elevation.
The topography within 2 miles of Surabaya contains only modest variations in elevation, with a maximum elevation change of 108 feet and an average elevation above sea level of 19 feet. Within 10 miles also contains only modest variations in elevation (430 feet). Within 50 miles contains only modest variations in elevation (10,951 feet).
The area within 2 miles of Surabaya is covered by artificial surfaces (99%), within 10 miles by water (41%) and artificial surfaces (37%), and within 50 miles by water (48%) and cropland (25%).
This report illustrates the typical weather in Surabaya, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.
Temperature and Dew Point
There are 2 weather stations near enough to contribute to our estimation of the temperature and dew point in Surabaya.
For each station, the records are corrected for the elevation difference between that station and Surabaya according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.
The estimated value at Surabaya is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Surabaya and a given station.
All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Algorithms 2nd Edition , by Jean Meeus.
All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.
Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.
Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.
Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .
Time zones for aiports and weather stations are provided by AskGeo.com .
Maps are © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.
The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.
We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.
We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.