| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 5.8° | — | 83.3mm | 12.1 | 30 |
| February | 7.5° | -0.1° | 68.7mm | 11.1 | 35 |
| March | 13.6° | 1° | 86.3mm | 12.6 | 53 |
| April | 19.3° | 6.5° | 74.1mm | 11.3 | 75 |
| May | 23.9° | 10.7° | 101.1mm | 13.5 | 73 |
| June | 28° | 15° | 83.5mm | 11.6 | 73 |
| July | 30° | 16° | 79.9mm | 9.4 | 69 |
| August | 30.3° | 16.4° | 65.2mm | 7 | 73 |
| September | 24.3° | 11.5° | 138.7mm | 10 | 80 |
| October | 18.9° | 8.1° | 64.7mm | 10 | 76 |
| November | 12.9° | 2.3° | 73.9mm | 11 | 55 |
| December | 6.2° | — | 76.8mm | 11 | 34 |
January in Banja Luka averages a daily high of 5.8°C. Expect roughly 12.1 wet days totalling 83.3mm. A hard month to visit for comfort alone.
February in Banja Luka averages a daily high of 7.5°C with nights around -0.1°C. Expect roughly 11.1 wet days totalling 68.7mm. Demanding conditions — pack for it and plan indoor options.
March in Banja Luka averages a daily high of 13.6°C with nights around 1°C. Expect roughly 12.6 wet days totalling 86.3mm. Demanding conditions — pack for it and plan indoor options.
April in Banja Luka averages a daily high of 19.3°C with nights around 6.5°C. Expect roughly 11.3 wet days totalling 74.1mm. Comfortable conditions for being outdoors all day.
May in Banja Luka averages a daily high of 23.9°C with nights around 10.7°C. Expect roughly 13.5 wet days totalling 101.1mm. Generally workable, with some weather to plan around.
June in Banja Luka averages a daily high of 28°C with nights around 15°C. Expect roughly 11.6 wet days totalling 83.5mm. Generally workable, with some weather to plan around.
July in Banja Luka averages a daily high of 30°C with nights around 16°C. Expect roughly 9.4 wet days totalling 79.9mm. Generally workable, with some weather to plan around.
August in Banja Luka averages a daily high of 30.3°C with nights around 16.4°C. Expect roughly 7 wet days totalling 65.2mm. Generally workable, with some weather to plan around.
September in Banja Luka averages a daily high of 24.3°C with nights around 11.5°C. Expect roughly 10 wet days totalling 138.7mm. Comfortable conditions for being outdoors all day.
October in Banja Luka averages a daily high of 18.9°C with nights around 8.1°C. Expect roughly 10 wet days totalling 64.7mm. Comfortable conditions for being outdoors all day.
November in Banja Luka averages a daily high of 12.9°C with nights around 2.3°C. Expect roughly 11 wet days totalling 73.9mm. Generally workable, with some weather to plan around.
December in Banja Luka averages a daily high of 6.2°C. Expect roughly 11 wet days totalling 76.8mm. A hard month to visit for comfort alone.
Each month scores out of 100. It starts at 100 and loses points for daytime highs outside a 20–27°C band, for wet days, and for nights below 2°C. Nothing else is weighted in — no crowd data, no prices, no opinion. Banja Luka peaks at 80.
Based on 30 years of records, April–June scores highest for comfort in Banja Luka, balancing daytime temperature against rainfall.
August is the warmest, averaging a daily high of 30.3°C.
September is the wettest, averaging 138.7mm of rain across roughly 10 wet days.
January is the coolest month, with average daily highs around 5.8°C.