Semnan in Fall
In fall (September, October and November), Semnan sees average daytime highs around 23°C and overnight lows near 12°C, with 18 mm of precipitation over about 5 wet days across the season. It is the 2nd-warmest season and the 3rd-wettest season.
Over the season highs ease from about 32°C in early September to 11°C by late November. The sky is clear or mostly clear about 76% of the time across fall, and the air most often feels dry.
Fall is Semnan's 2nd-best season to visit on our travel score. For the whole year in context, see Semnan's year-round climate.
- Avg daytime high
- 23°C
- 2nd-warmest season
- Avg overnight low
- 12°C
- Precipitation
- 18 mm
- 5 wet days
- Avg wind
- 9 km/h
- Travel score
- 7.0
- 2nd-best season
- Months
- Sep · Oct · Nov
Temperature in Semnan in Fall
Over the season highs ease from about 32°C in early September to 11°C by late November.
A typical fall day in Semnan reaches about 23°C and drops to 12°C overnight. The warmest of the three months is September, the coolest November.
How fall really feels in Semnan
Once humidity and wind are folded in, fall brings about 6 days that feel above 32°C and 0 that feel at or below 0°C.
The story in fall is heat — humidity pushes the afternoon "feels like" well above the raw temperature.
Semnan weather by month
How the three fall months (September, October and November) compare with the rest of the year — the season's months are highlighted.
| Month | High / Low (°C) | Rainfall (mm) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 8° / -0° | 12 | 3.2 | 1.7 | 9.9 | 1.6 |
| Feb | 10° / 1° | 14 | 2.9 | 1.4 | 10.7 | 2.9 |
| Mar | 16° / 6° | 18 | 3.9 | 0.9 | 11.7 | 5.7 |
| Apr | 22° / 11° | 13 | 2.7 | 0.1 | 12.9 | 8.0 |
| May | 28° / 17° | 5 | 1.3 | 0 | 13.9 | 7.6 |
| Jun | 33° / 21° | 1 | 0.3 | 0 | 14.4 | 4.5 |
| Jul | 36° / 24° | 1 | 0.3 | 0 | 14.2 | 2.9 |
| Aug | 35° / 23° | 1 | 0.3 | 0 | 13.3 | 3.8 |
| Sep | 30° / 18° | 2 | 0.5 | 0 | 12.2 | 6.8 |
| Oct | 23° / 12° | 5 | 1.1 | 0 | 11.1 | 8.8 |
| Nov | 15° / 6° | 11 | 3 | 0.2 | 10.1 | 5.4 |
| Dec | 9° / 1° | 10 | 3.1 | 0.9 | 9.6 | 2.3 |
Cloud cover in Fall
The sky is clear or mostly clear about 76% of the time across fall.
Chance of precipitation in Fall
Semnan gets around 18 mm of rain and snow over 5 wet days across fall. The line is the day-by-day chance of measurable precipitation.
Humidity in Fall
Most of fall feels dry — the stacked bands show each day's mix of comfort levels, read off the dew point.
Wind in Fall
Winds average 9 km/h across fall.
Sunrise & sunset in Fall
Daylight runs from about 12 h 48 min in early September to 9 h 48 min by late November. The lit band spans sunrise to sunset each day.
Solar energy in Fall
Average shortwave solar energy reaching the ground each day across fall, about 4.6 kWh/m².
Is fall a good time to visit Semnan?
Our two travel scores rate fall for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal), averaged across the three months.
fall is one of the better times to visit Semnan for general sightseeing.
What to pack for Semnan in Fall
From fall's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In fall, Semnan sees daytime highs around 23°C and nights near 12°C. Pack light clothes. Worth having: a warm layer and sun protection. About 5 days see rain.
UV index in Semnan in Fall
Clear-sky midday UV across fall averages around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Semnan peaks around July 19 at about 11 (extreme) — sunscreen, a hat and midday shade are essential. It bottoms out near January 10 at about 3 (moderate).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 11 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 3 | 5 | 5 | 8 | 10 | 10 | 11 | 10 | 8 | 6 | 4 | 3 |
| Level | Moderate | High | Moderate | Very high | Very high | Very high | Extreme | Extreme | Very high | High | Moderate | Moderate |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 3 | Moderate |
| Feb | 5 | High |
| Mar | 5 | Moderate |
| Apr | 8 | Very high |
| May | 10 | Very high |
| Jun | 10 | Very high |
| Jul | 11 | Extreme |
| Aug | 10 | Extreme |
| Sep | 8 | Very high |
| Oct | 6 | High |
| Nov | 4 | Moderate |
| Dec | 3 | Moderate |
Air quality in Semnan in Fall
Average fine-particle pollution (PM2.5) through the year — so you can see where fall falls, not just the annual average.
Air quality in Semnan is worst in December — around 46 µg/m³ PM2.5 (poor), about 2.1× the cleanest month (August, 22 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 43 | 41 | 38 | 40 | 34 | 23 | 23 | 22 | 28 | 32 | 39 | 46 |
| Level | Poor | Poor | Poor | Poor | Moderate | Moderate | Moderate | Moderate | Moderate | Moderate | Poor | Poor |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 43 | Poor |
| Feb | 41 | Poor |
| Mar | 38 | Poor |
| Apr | 40 | Poor |
| May | 34 | Moderate |
| Jun | 23 | Moderate |
| Jul | 23 | Moderate |
| Aug | 22 | Moderate |
| Sep | 28 | Moderate |
| Oct | 32 | Moderate |
| Nov | 39 | Poor |
| Dec | 46 | Poor |
Where is Semnan?
Semnan sits at 35.6°N, 53.4°E, 1,148 m above sea level, in Iran. The nearest listed city is Mahdishahr, 15 km away.
Topography around Semnan
How much the land rises and falls, and what covers it, within 3, 16 and 80 km of Semnan.
Within 3 km, the terrain around Semnan has only modest variations in elevation — a maximum elevation change of 144 m around an average of 1,149 m above sea level; within 16 km, very significant variations in elevation — a maximum elevation change of 1,254 m; within 80 km, extreme variations in elevation — a maximum elevation change of 3,375 m.
The land around Semnan is covered by artificial surfaces (59%) and bare terrain (20%) within 3 km, bare terrain (84%) within 16 km, and bare terrain (67%) and grassland (22%) within 80 km.
Iran travel facts
- Travel advisory
- Level 4
- Do Not Travel
- Power plugs
- Type C / F
- 220 V · 50 Hz
- Prices
- ≈ 352% of US
- price level, 2025
- GDP per capita
- $3,924
- 2025
- Happiness
- 5.2 / 10
- World Happiness, 2025
- Safe drinking water
- 94%
- of population, 2024
- Homicide rate
- 2.4
- per 100k, 2014
- Road deaths
- 21.5
- per 100k/yr, 2019
- Income group
- Upper middle
- World Bank
- English
- Low
- EF EPI 492
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Semnan (35.5769°, 53.392°, elevation 1,148 m), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google.