Climate Insights for Kostajnica

The climate in Kostajnica is temperate. The average annual temperature is 13°C and approximately 939mm of precipitation falls per year. Kostajnica receives a notable amount of rainfall throughout the year, including during its driest month. Kostajnica is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: July, August, June. The coldest months are January, December, February, when temperatures can drop to -1°C. Snowfall occurs from January to December, with around 53cm accumulating over the season.

Temperatures in Kostajnica vary considerably across the year, with a 31°C difference between the coldest and warmest months. The warmest month is July, when average highs reach 30°C and the mean temperature sits around 24°C. The coldest month is January, when overnight lows fall to -1°C and the daily average is 2°C. On average, daily temperatures fluctuate by about 10°C between overnight lows and afternoon highs. The sharpest temperature change occurs between October and November, with a 5°C shift in average temperatures.

Kostajnica is a moderately rainy area, receiving approximately 939mm of precipitation annually, which averages out to around 78mm per month. The wettest month is May, averaging 114mm of rainfall. September and November also tend to see above-average precipitation. The driest month is March, with just 58mm. That's 56mm less than May, the wettest month. Rainfall is relatively evenly distributed throughout the year, so there is no pronounced dry or wet season to plan around. Snowfall is a regular feature from January to December, with around 53cm accumulating over the season. January typically sees the most snow at around 19cm.

Kostajnica is relatively calm, with an average annual wind speed of 11km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is March, averaging 13km/h, though still comfortable for most outdoor activities. The calmest conditions occur in August, with average winds dropping to 10km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 3km/h between the calmest and windiest months.

It is currently spring in Kostajnica, which began on March 20, 2026. Kostajnica is in the Northern Hemisphere, where spring begins in March, summer in June, autumn in September, and winter in December. The warmest period peaks in July at around 30°C, while the coldest stretch bottoms out in January near -1°C. Summer is next, beginning on June 21, 2026 — 89 days from now.

The best time to visit Kostajnica is during June, July, August and September, when the weather is most comfortable for travellers. During these months, average temperatures hover around 21°C with modest rainfall averaging 82mm per month. By contrast, January can be quite cold with temperatures dropping to -1°C. Despite being the best months overall, some rain is still likely — pack a waterproof layer and plan a mix of indoor and outdoor activities.

The table below shows monthly climate averages for Kostajnica 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. Snow is measured in centimetres (cm) and reflects average monthly snowfall accumulation. 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.