| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 9.5° | -0.2° | 13.5mm | 3.4 | 56 |
| February | 12.4° | 2.3° | 17.5mm | 4 | 68 |
| March | 19° | 7.9° | 14.7mm | 3.9 | 89 |
| April | 25° | 13.1° | 14.9mm | 4.8 | 90 |
| May | 30.9° | 19.1° | 11.8mm | 3.6 | 77 |
| June | 36.7° | 24.4° | 6.8mm | 1.7 | 58 |
| July | 38.6° | 26.9° | 3.2mm | 1 | 52 |
| August | 37.1° | 24.6° | 3mm | 0.9 | 58 |
| September | 33.3° | 20.8° | 3mm | 1 | 73 |
| October | 25.8° | 13.7° | 5.7mm | 1.8 | 96 |
| November | 16.6° | 7° | 11.5mm | 3.4 | 82 |
| December | 11.3° | 2.3° | 17.7mm | 3.6 | 65 |
January in Semnan averages a daily high of 9.5°C with nights around -0.2°C. Expect roughly 3.4 wet days totalling 13.5mm. Generally workable, with some weather to plan around.
February in Semnan averages a daily high of 12.4°C with nights around 2.3°C. Expect roughly 4 wet days totalling 17.5mm. Generally workable, with some weather to plan around.
March in Semnan averages a daily high of 19°C with nights around 7.9°C. Expect roughly 3.9 wet days totalling 14.7mm. Comfortable conditions for being outdoors all day.
April in Semnan averages a daily high of 25°C with nights around 13.1°C. Expect roughly 4.8 wet days totalling 14.9mm. Comfortable conditions for being outdoors all day.
May in Semnan averages a daily high of 30.9°C with nights around 19.1°C. Expect roughly 3.6 wet days totalling 11.8mm. Comfortable conditions for being outdoors all day.
June in Semnan averages a daily high of 36.7°C with nights around 24.4°C. Rain is rare — about 1.7 wet days and 6.8mm across the month. Generally workable, with some weather to plan around.
July in Semnan averages a daily high of 38.6°C with nights around 26.9°C. Rain is rare — about 1 wet days and 3.2mm across the month. Demanding conditions — pack for it and plan indoor options.
August in Semnan averages a daily high of 37.1°C with nights around 24.6°C. Rain is rare — about 0.9 wet days and 3mm across the month. Generally workable, with some weather to plan around.
September in Semnan averages a daily high of 33.3°C with nights around 20.8°C. Rain is rare — about 1 wet days and 3mm across the month. Generally workable, with some weather to plan around.
October in Semnan averages a daily high of 25.8°C with nights around 13.7°C. Rain is rare — about 1.8 wet days and 5.7mm across the month. Comfortable conditions for being outdoors all day.
November in Semnan averages a daily high of 16.6°C with nights around 7°C. Expect roughly 3.4 wet days totalling 11.5mm. Comfortable conditions for being outdoors all day.
December in Semnan averages a daily high of 11.3°C with nights around 2.3°C. Expect roughly 3.6 wet days totalling 17.7mm. Generally workable, with some weather to plan around.
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. Semnan peaks at 96.
Based on 30 years of records, March–April scores highest for comfort in Semnan, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 38.6°C.
December is the wettest, averaging 17.7mm of rain across roughly 3.6 wet days.
January is the coolest month, with average daily highs around 9.5°C.