Weather in Boston 🇺🇸
Monthly weather averages & travel planning
May
Avg Temp
19°C
Rain Days
11 days
Sun Hours
10 hrs
Humidity
65%
North America › 🇺🇸 United States › Boston
Updated: March 2026
Is May a Good Time to Visit Boston?
6/10
Good
May is a good time to visit Boston (6/10). With 10 daily sunshine hours and only 11 rain days, this month delivers genuinely reliable outdoor conditions, ranking it 4th sunniest of the year in Boston. Culture-focused travellers and those who prefer lighter crowds will find May a practical choice, with prices running lower than peak July without sacrificing all the good weather. June offers a similar profile at lower hotel rates if dates are flexible. The main practical note: Boston'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.
vs April:14°C avg high
Boston's May weather is shaped by atmospheric forces that make the data more than just numbers. The 19°C average high reflects a transitional pressure pattern where mid-latitude westerlies alternately bring mild maritime air and cooler polar intrusions. As a result, 10 daily sunshine hours are recorded on average, and rainfall of 80mm is distributed across approximately 11 days because precipitation events tend to be frequent but short-lived.
19°C
66°F
Avg High
10°C
50°F
Avg Low
11 days
80 mm total
Rain Days
10h
per day avg
Sunshine
65%
Moderate
Humidity
Temperature in Boston in May
The 9°C day-night temperature range is typical for continental climates: a light jacket in the morning that you shed by midday and need again after sunset. 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. Wind averages 20 km/h, light enough to be refreshing on warm days but noticeable in open coastal areas or elevated viewpoints. In Fahrenheit: 66°F average high, 50°F overnight low. Data sourced from Open-Meteo ERA5 climate reanalysis (1991–2020 normals).
Temperature Trends
High
Low
Rainfall (mm)
0-20 mm21-50 mm51-100 mm100+ mm
What to Wear in Boston in May
Morning10°CBefore the day warms up
Afternoon19°CPeak daytime temperature
Evening13°CAfter sunset cools down
Packing for Boston in May means dressing for 19°C days and 10°C evenings. A light cotton tee with a casual overshirt works well at 19°C, the overshirt doubles as a layer for air-conditioned venues. Evening temperatures settle at 10°C, a modest 9°C drop that a light cardigan or denim jacket covers. Comfortable walking trainers are the versatile choice for both outdoor sightseeing and indoor venues. A compact foldable umbrella weighs almost nothing and earns its keep across 11 potential rainy days.
Local tip: Layers are more practical than a single heavy garment in Boston. The day-to-evening temperature shift rewards packing a versatile mid-layer you can add or remove as conditions change.
Events in Boston in May
May has no major festivals or public holidays in Boston, 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 Boston in May
Based on 19°C average highs and 11 rainy days
- Light jacket or cardigan for cooler evenings
- Mix of short and long-sleeve layers
- Comfortable walking shoes with good arch support
- Compact folding umbrella
- Waterproof outer layer or packable rain jacket
- Quick-dry clothing that recovers fast after a shower
- Universal travel adapter
- Small day pack for city exploration
- Reusable water bottle
Best Activities in Boston in May
- Explore outdoor markets and street food stallsMid-morning (10am-12pm)At 19°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
- Try the seasonal farmer's market for local produce and street foodSaturday morning markets typically 8am-1pmMay seasonal produce is at peak availability, offering dishes not found at other times of year
Why is Boston mild in May?
May marks the transition into warmer conditions in Boston, as the sun angle climbs and day length extends. Temperatures averaging 19°C by day and 10°C overnight reflect a city shaking off winter: the morning air still carries a cool edge, but afternoons are noticeably warmer than even four weeks prior. At 42 degrees north latitude, spring is one of the most dynamic periods in the annual cycle, with weekly temperature changes that can be larger than the month-to-month shifts of summer. This volatility is part of the appeal: Boston in May has a freshness and energy that peak-summer heat tends to mute. Layers remain essential, but there are reliable pockets of warmth that reward patience. 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
Boston in May
In May, Boston experiences average highs of 19°C (66°F) and lows of 10°C (50°F). Expect around 11 rainy days and 10 hours of sunshine per day, with humidity averaging 65%. The 9°C gap between daytime and overnight temperatures is worth planning around: light layers work for most visitors during the day, but an extra jacket is essential for evenings. UV index averages 9, so sun protection is advisable on clear days.
Boston typically sees 11 rainy days in May, with total precipitation of around 80mm. Rain is moderate and manageable. Showers tend to pass quickly, and a light rain layer or foldable umbrella is sufficient protection for most days. For context, the driest month in Boston typically sees 4-6 fewer rain days than May.
Pack light layers, a light jacket for evenings, comfortable walking shoes, and sunscreen for Boston in May. Daytime temperatures of 19°C are pleasant, but the evening drop to 10°C means a jacket is essential if you plan to be out after dark. With 11 rainy days, bring a compact umbrella or waterproof jacket for unexpected showers. Comfortable walking shoes are a priority given the amount of ground most visitors cover.
Yes, May is an excellent time to visit Boston. With 10 daily sunshine hours and only 11 rainy days, conditions are ideal for sightseeing and outdoor activities. Temperatures averaging 19°C during the day are comfortable for long walks and outdoor dining. This is peak travel season, so booking accommodation in advance and arriving at popular attractions early in the morning helps avoid the busiest periods.
The average high temperature in Boston in May is 19°C (66°F), and the average low is 10°C (50°F). The mean daily temperature is approximately 15°C (58°F). The day-to-night range of 9°C is moderate, meaning a single light jacket covers most situations. These are 30-year climate normals based on the 1991 to 2020 reference period; individual years will vary, particularly in transitional months like spring and autumn.
The best month to visit Boston is generally July. July offers the most sunshine at 12 hours per day and only 10 rainy days. Average temperatures reach 28°C, making it comfortable for sightseeing, outdoor dining, and exploring the city. If your travel dates are flexible, planning your trip around July gives you the best chance of dry, bright weather.
May is shoulder or low season in Boston, meaning fewer tourists and generally lower prices than peak months. With 10 sunshine hours and 11 rainy days, the weather is less of a draw for mass tourism. This is an advantage for travellers who prefer a quieter, more relaxed experience with shorter queues and easier accommodation availability.
In May, Boston suits a range of activities thanks to mild temperatures around 19°C. Mix of indoor and outdoor activities works well given the moderate chance of rain. Top options include exploring historic neighbourhoods, visiting museums and galleries, local food markets, and day trips to surrounding areas. With 10 hours of sunshine, parks and waterfront walks are particularly enjoyable.
May ranks 4th sunniest of the year in Boston, with an average 10 daily sunshine hours. The driest months are September, February, and August. July is the hottest month (28°C avg high); January is the coolest (2°C). From here, temperatures rise 6°C into June. Compared to last month (April: 14°C high, 11 rain days), May is warmer and equally dry. May sits in the middle of the annual sunshine ranking for Boston, offering a reasonable balance of good weather and manageable crowds.
Year-Round Climate
| Month | High | Low | Rain Days | Sun | Details |
|---|---|---|---|---|---|
| January | 2°C | -6°C | 10 | 6h | View |
| February | 3°C | -6°C | 9 | 7h | View |
| March | 7°C | -2°C | 11 | 8h | View |
| April | 14°C | 4°C | 11 | 9h | View |
| May | 19°C | 10°C | 11 | 10h | View |
| June | 25°C | 15°C | 10 | 11h | View |
| July | 28°C | 19°C | 10 | 12h | View |
| August | 27°C | 18°C | 9 | 11h | View |
| September | 23°C | 15°C | 8 | 9h | View |
| October | 16°C | 9°C | 10 | 8h | View |
| November | 10°C | 3°C | 10 | 6h | View |
| December | 5°C | -2°C | 11 | 6h | View |
January
10 rain days, 6h sun
2°-6°
February
9 rain days, 7h sun
3°-6°
March
11 rain days, 8h sun
7°-2°
April
11 rain days, 9h sun
14°4°
May
11 rain days, 10h sun
19°10°
June
10 rain days, 11h sun
25°15°
July
10 rain days, 12h sun
28°19°
August
9 rain days, 11h sun
27°18°
September
8 rain days, 9h sun
23°15°
October
10 rain days, 8h sun
16°9°
November
10 rain days, 6h sun
10°3°
December
11 rain days, 6h sun
5°-2°
Other Months in Boston
Plan Your Trip to Boston
Nearby Destinations
Cities within 500 km with comparable weather conditions
Data Sources for Boston
Climate normals represent 30-year averages (1991-2020). Individual years may vary.