Climate Overview
The climate in Pematangsiantar is warm and mild. The average annual temperature is 25°C and approximately 3342mm of precipitation falls per year. Pematangsiantar receives a notable amount of rainfall throughout the year, including during its driest month. Pematangsiantar sits near the equator, so seasonal temperature differences are minimal throughout the year.
Temperature
Pematangsiantar has relatively stable temperatures year-round, staying within a 9°C range. The warmest month is May, when average highs reach 30°C and the mean temperature sits around 25°C. February is the coolest month, with minimum temperatures around 21°C and an average of 24°C. Daily temperature variation is modest, with an average difference of 7°C between highs and lows.
Precipitation
Pematangsiantar is a very wet location, receiving approximately 3342mm of precipitation annually, which averages out to around 278mm per month. The wettest month is November, averaging 389mm of rainfall. October and December also tend to see above-average precipitation. The driest month is February, with just 188mm. That's 201mm less than November, the wettest month. Rainfall is relatively evenly distributed throughout the year, so there is no pronounced dry or wet season to plan around.
Wind
Pematangsiantar is relatively calm, with an average annual wind speed of 8km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is February, averaging 9km/h, though still comfortable for most outdoor activities. The calmest conditions occur in July, with average winds dropping to 7km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 2km/h between the calmest and windiest months.
Seasons
89 days until Summer
It is currently spring in Pematangsiantar, which began on March 20, 2026. Pematangsiantar sits near the equator, so the traditional four-season cycle is less pronounced — temperatures remain relatively stable year-round. The warmest period peaks in May at around 30°C, while the coldest stretch bottoms out in February near 21°C. Summer is next, beginning on June 21, 2026 — 89 days from now.
Spring
Temperatures range from 22 to 30°C. Rainfall is heavy, totalling around 722mm across the season with a monthly average of 241mm. Winds are generally light, averaging 8km/h. An umbrella or waterproof jacket is advisable as spring showers are frequent.
Summer
Temperatures range from 22 to 30°C. Rainfall is heavy, totalling around 780mm across the season with a monthly average of 260mm. Winds are generally light, averaging 7km/h. Light, breathable clothing is ideal — perfect conditions for outdoor activities.
Autumn
Temperatures range from 22 to 29°C. Rainfall is heavy, totalling around 1066mm across the season with a monthly average of 355mm. Winds are generally light, averaging 8km/h. A waterproof jacket and sturdy footwear are recommended as rain becomes more frequent.
Winter
Temperatures range from 21 to 29°C. Rainfall is heavy, totalling around 774mm across the season with a monthly average of 258mm. Winds are generally light, averaging 8km/h. A light jacket or sweater is usually sufficient, though cooler evenings may call for an extra layer.
Monthly Climate Data
The table below shows monthly climate averages for Pematangsiantar based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.
