Tehran Weather in May
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Asia › 🇮🇷 Iran › Tehran
Updated: March 2026
Is May a Good Time to Visit Tehran?
May is a good time to visit Tehran (7/10). With 12 daily sunshine hours and only 5 rain days, this month delivers genuinely reliable outdoor conditions, ranking it 4th sunniest of the year in Tehran. Culture-focused travellers and those who prefer lighter crowds will find May a practical choice, with prices running lower than peak June without sacrificing all the good weather. April offers a similar profile at lower hotel rates if dates are flexible. The main practical note: Tehran's popular sites are busiest between 10am and 3pm regardless of season. Arriving at opening time or after 4pm makes a significant difference to the experience. Planning tips: accommodation is generally available without long lead times, and flight prices are typically lower than peak season. Flexible travellers will find the best deals by booking 2-4 weeks ahead. Mid-week arrivals consistently unlock lower hotel rates than weekend check-ins.
Tehran's May climate peaks at 27°C each afternoon before cooling to 14°C overnight. 12 daily sunshine hours and just 5 wet days mean the odds of a fine day are solidly in your favour. It is an excellent window for outdoor itineraries.
27°C
Avg High
14°C
Avg Low
5 days
Rain Days
12h
Sunshine
65%
Humidity
Temperature in Tehran in May
The 13°C day-to-night swing is large enough to require a deliberate layering strategy, what works at noon will be noticeably cold by 10pm. Humidity averages 65%, which is comfortable for most visitors. On warmer days, lighter fabrics help with the mild stickiness in the afternoon. UV index averages 9 this month, classed as high to very high. SPF 30+ sunscreen, a brim hat, and sunglasses are not optional between 10am and 4pm. Winds are calm at an average 13 km/h, so wind-chill is not a factor in planning your clothing. In Fahrenheit: 81°F average high, 57°F overnight low. Data sourced from Open-Meteo ERA5 climate reanalysis (1991–2020 normals).
Temperature in May
Monthly Precipitation (mm)
What to Wear in Tehran in May
Packing for Tehran in May means dressing for 27°C days and 14°C evenings. A light cotton tee with a casual overshirt works well at 27°C, the overshirt doubles as a layer for air-conditioned venues. Evenings drop 13°C to around 14°C, a notable shift that catches underprepared visitors off guard. Pack a dedicated evening layer. Comfortable walking trainers are the versatile choice for both outdoor sightseeing and indoor venues. For temple and religious site visits, carry a lightweight scarf or sarong to cover shoulders and knees, required at most major sites across the region.
Local tip: Temple and religious site visits require covered shoulders and knees in most of Tehran's heritage areas. A lightweight scarf or sarong weighs almost nothing and solves the problem instantly.
Events in Tehran in May
May has no major festivals or public holidays in Tehran, which is one of its practical advantages for independent travellers. Attractions run at lower capacity than during peak event periods, queues are shorter, and accommodation is easier to find without needing to book many months in advance. Local restaurants, markets, and transport operate at a relaxed pace, making this an ideal time for visitors who prefer a more authentic, unhurried experience of everyday city life rather than large crowds drawn in by a single major headline event.
What to Pack for Tehran in May
Based on 27°C average highs and 5 rainy days
- Light layers for morning and evening
- Breathable T-shirts and comfortable trousers
- UV-protective sunglasses
- Quick-dry travel towel
- Anti-chafe balm for long walking days
- Moisture-wicking synthetic fabrics for active days
- SPF 30+ sunscreen
- Comfortable walking shoes (a second pair lets the first air out overnight)
- Universal travel adapter
- Small day pack for city exploration
- Reusable water bottle
Best Activities in Tehran in May
- Explore outdoor markets and street food stallsMid-morning (10am-12pm)At 27°C, the temperature is ideal for extended walking without overheating
- Guided walking tour of the historic centreMorning or late afternoonComfortable temperatures allow several hours on foot without fatigue
- Visit rooftop viewpoints and observation decksGolden hour (1 hour before sunset)Warm clear evenings provide exceptional visibility for panoramic photography
- Day trip to the surrounding countryside or coastFull day (depart by 8am)May is reliably dry enough for rural day trips without weather risk
- Afternoon in a world-class museum or galleryAfternoon (2-5pm)Pairs well with outdoor morning activities and provides a mid-day rest from sightseeing
- Coffee-house or traditional cafe culture experienceMid-morning or post-lunchA cultural ritual in this region that rewards slow appreciation regardless of weather
- Evening live music, theatre, or opera performanceEvening shows typically at 7-9pmConsistent evening temperatures make getting to and from evening venues comfortable
- Visit the main botanical garden or city park at seasonal peakYear-round; best light in morningMay brings distinct seasonal changes to public green spaces worth exploring
- Seek out chilled local specialities: cold-brew tea, ice desserts, or chilled seafood at street-level stallsAny time; most atmospheric in evening marketsHot-weather street food culture peaks in May, with vendors setting up specifically for warm evenings
Why is Tehran warm in May?
Tehran's May heat is driven by the Asian summer monsoon system, as the low-pressure cell that forms over the heated landmass draws warm, humid air from the oceans. The result is temperatures averaging 27°C with high moisture in the air. Overnight temperatures remain elevated at 14°C, as clouds and humidity prevent the earth from radiating heat away after sunset. Climate data: Open-Meteo ERA5 (1991–2020).
Sunshine Hours
The average number of hours per day with direct sunlight. Calculated from satellite measurements. Days with more than 7 hours of sunshine are ideal for outdoor activities. Under 3 hours means overcast conditions dominate.
UV Index
A scale from 0-11+ measuring ultraviolet radiation intensity. UV 0-2: Minimal risk. UV 3-5: Moderate -- wear sunscreen. UV 6-7: High -- hat and SPF 30+ essential. UV 8-10: Very High -- limit midday exposure. UV 11+: Extreme -- seek shade between 10am-4pm.
Rain Days
A rain day is counted when precipitation exceeds 0.1mm. This threshold captures even light drizzle. Unlike total rainfall in mm, rain days tells you how often you might need an umbrella, which is useful for planning outdoor activities.
Humidity
Relative humidity as a percentage. Below 40%: Dry -- skin and throat may feel parched. 40-60%: Comfortable -- ideal for most people. 60-80%: Sticky -- light, breathable fabrics recommended. Above 80%: Muggy -- heat feels more intense; quick-dry clothing is essential.
Frequently Asked Questions: Tehran in May
May ranks 4th sunniest of the year in Tehran, with an average 12 daily sunshine hours. The driest months are July, August, and September. July is the hottest month (36°C avg high); January is the coolest (6°C). From here, temperatures rise 6°C into June. Compared to last month (April: 20°C high, 9 rain days), May is warmer and drier. May sits in the middle of the annual sunshine ranking for Tehran, offering a reasonable balance of good weather and manageable crowds.
Year-Round Climate
Plan Your Trip to Tehran
Data Sources for Tehran
Climate normals represent 30-year averages (1991-2020). Individual years may vary.