Smithtown, United States experiences average highs of 16°C (61°F) and lows of 10°C (50°F) throughout the year. Rainfall is moderate, averaging about 10 rainy days per month. Sunshine is abundant, averaging about 9 hours per day. Average highs have cooled by 0.6°C (1.1°F) across the available records.
Smithtown, United States Weather & Climate 2026
Monthly climate averages for Smithtown, United States. Based on 10-year ERA5 reanalysis data.
Climate Overview
Drier season: Jan–Nov 
Wetter season: Mar–Dec At-a-Glance Climate Summary
Live Weather & Air Quality
Key figures
Climate Score
5.4/10
Best: June, August, September
UV Index
5
Low
Temperature 16°C / 10°C
Feels Like 14°C / 7°C
Rainy Days 10
Rainfall 104 mm
Sunshine 9 h
Humidity 74%
Wind Speed 25 km/h
Dew Point 8°C
Snow Days 4 days
Frost Days 9 days
Hottest Month
28°C
July
Avg Low22°C
Rain11days
Coldest Month
-1°C
January
Avg High4°C
Rain10days
Driest Month
8days
November
Avg High12°C
Avg Low6°C
Windiest Month
28 km/h
January (Gusts 48)
Sea Temperature
4°C – 24°C
Warmest water: July (
23.5°C
)
Worst Time to Visit
Consider avoiding January, February, March, December due to very cold temperatures, frequent rain.
Sun Position
Sunrise 05:22
Daylight 15.1h
Sunset 20:27
Live conditions—
Smithtown on the map · live conditions
Smithtown, United States
- Continent
- Americas
- Country
- United States
- City
- Smithtown
- Population
- 26.5K
- Elevation
- 18 m
- Coordinates
- 40.86°, -73.20°
Seasonal Breakdown
Spring
Mar–May
Avg High 14°C
Avg Low 7°C
Rain 11 days/mo
Summer
Jun–Aug
Avg High 26°C
Avg Low 20°C
Rain 10 days/mo
2/3 best months
Autumn
Sep–Nov
Avg High 18°C
Avg Low 12°C
Rain 9 days/mo
1/3 best months
Winter
Dec–Feb
Avg High 5°C
Avg Low 0°C
Rain 10 days/mo
Climate Charts
Based on historical averages (2016–2025)
Monthly Temperatures
HighLowShaded bands show the typical range across the available yearly records.
Line chart showing monthly temperatures. Jan: 4°C / -1°C . Feb: 6°C / -1°C . Mar: 9°C / 2°C . Apr: 14°C / 7°C . May: 19°C / 12°C . Jun: 25°C / 18°C . Jul: 28°C / 22°C . Aug: 27°C / 21°C . Sep: 23°C / 18°C . Oct: 18°C / 13°C . Nov: 12°C / 6°C . Dec: 6°C / 1°C .
Monthly Rainfall
Rainfall
Bar chart showing monthly rainfall. Jan: 101 mm. Feb: 103 mm. Mar: 111 mm. Apr: 111 mm. May: 108 mm. Jun: 73 mm. Jul: 102 mm. Aug: 88 mm. Sep: 106 mm. Oct: 123 mm. Nov: 89 mm. Dec: 132 mm.
Monthly Humidity
Humidity
Line chart showing monthly humidity. Jan: 70%. Feb: 72%. Mar: 69%. Apr: 71%. May: 76%. Jun: 75%. Jul: 77%. Aug: 77%. Sep: 77%. Oct: 76%. Nov: 70%. Dec: 73%.
Monthly Wind Speed
Wind SpeedGusts
Bar chart showing monthly wind speed. Jan: 28 km/h . Feb: 27 km/h . Mar: 28 km/h . Apr: 27 km/h . May: 23 km/h . Jun: 22 km/h . Jul: 21 km/h . Aug: 21 km/h . Sep: 22 km/h . Oct: 25 km/h . Nov: 28 km/h . Dec: 28 km/h .
Sunshine
Sunshine
Sunshine: Jan: 6h. Feb: 7h. Mar: 8h. Apr: 9h. May: 10h. Jun: 12h. Jul: 12h. Aug: 11h. Sep: 9h. Oct: 8h. Nov: 7h. Dec: 6h.
Sea Temperature
Sea Temperatureswim
Line chart showing monthly sea temperature. Jan: 4°C . Feb: 4°C . Mar: 5°C . Apr: 9°C . May: 14°C . Jun: 18°C . Jul: 24°C . Aug: 23°C . Sep: 22°C . Oct: 18°C . Nov: 13°C . Dec: 7°C .
UV Index
UV Index
Bar chart showing monthly UV index. Jan: UV 2. Feb: UV 3. Mar: UV 5. Apr: UV 5. May: UV 6. Jun: UV 7. Jul: UV 7. Aug: UV 7. Sep: UV 5. Oct: UV 4. Nov: UV 3. Dec: UV 2.
Monthly Daylight Hours
Daylight12h reference
Monthly Dew Point & Comfort
Dew Point Dry Comfortable Humid Muggy Oppressive
Snow Days
Snow DaysSnowfall
Snow Days: Jan: 5 days. Feb: 6 days. Mar: 3 days. Apr: 0 days. May: 0 days. Jun: 0 days. Jul: 0 days. Aug: 0 days. Sep: 0 days. Oct: 0 days. Nov: 1 days. Dec: 3 days.
Climate Trends
Average highs have cooled by 0.6°C (1.1°F) across the available records. Average rainfall has remained broadly steady.
2016 to 2025
Avg high Avg rainfall
Climate summary
| Last 12 months | All years | |
|---|---|---|
| Hottest month | Jul 2025 · 28°C | Jul · 28°C |
| Coldest month | Jan 2025 · -3°C | Jan · -1°C |
| Wettest month | Oct 2025 · 163 mm | Dec · 132 mm |
| Windiest month | Dec 2025 · 32 km/h | Jan · 28 km/h |
Month-by-Month Weather Table
January
Poor 
February
Poor March
Poor April
Fair May
Good June best
Excellent July
Good August best
Excellent September best
Excellent October
Good November
Fair December
Poor | Month | Temp | Feels Like | Rain | Sun | Humidity | UV | Status | Details |
|---|---|---|---|---|---|---|---|---|
| January | 4°C / -1°C | -1°C / -7°C | 10days (101 mm) Wet | 6.1h Fair | 70% Muggy | 2.4 Moderate | Poor | View Details |
| February | 6°C / -1°C | 1°C / -6°C | 10days (103 mm) Wet | 6.8h Fair | 72% Muggy | 3.4 Moderate | Poor | View Details |
| March | 9°C / 2°C | 5°C / -3°C | 11days (111 mm) Wet | 8.4h Good | 69% Muggy | 4.6 Moderate | Poor | View Details |
| April | 14°C / 7°C | 12°C / 2°C | 11days (111 mm) Wet | 9.2h Good | 71% Muggy | 5.4 High | Fair | View Details |
| May | 19°C / 12°C | 19°C / 9°C | 12days (108 mm) Wet | 10h Excellent | 76% Humid | 6.3 High | Good | View Details |
| June best | 25°C / 18°C | 26°C / 17°C | 9days (73 mm) Wet | 11.6h Excellent | 75% Muggy | 7.1 Very High | Excellent | View Details |
| July | 28°C / 22°C | 31°C / 24°C | 11days (102 mm) Wet | 11.9h Excellent | 77% Humid | 7.3 Very High | Good | View Details |
| August best | 27°C / 21°C | 29°C / 23°C | 10days (88 mm) Wet | 11h Excellent | 77% Humid | 6.6 High | Excellent | View Details |
| September best | 23°C / 18°C | 24°C / 18°C | 9days (106 mm) Wet | 9.1h Good | 77% Humid | 5.1 High | Excellent | View Details |
| October | 18°C / 13°C | 17°C / 10°C | 10days (123 mm) Wet | 7.7h Good | 76% Humid | 4.1 Moderate | Good | View Details |
| November | 12°C / 6°C | 8°C / 2°C | 8days (89 mm) Wet | 7h Good | 70% Muggy | 2.9 Moderate | Fair | View Details |
| December | 6°C / 1°C | 2°C / -4°C | 11days (132 mm) Wet | 5.7h Fair | 73% Muggy | 2.1 Moderate | Poor | View Details |
Compare Nearby City Climates
Frequently Asked Questions
The best months to visit Smithtown are June, August, September, when temperatures are comfortable and rainfall is at its lowest. This is based on 10-year climate averages for Smithtown, scoring temperature, rainfall, humidity, and sunshine hours.
The hottest month in Smithtown is July, with average daytime highs of 28°C (82°F). Plan outdoor activities for early morning or late afternoon if visiting during this period.
The coldest month in Smithtown is January, with average overnight lows of -1°C (30°F). Pack warm layers and expect shorter daylight hours during this period.
The wettest month in Smithtown is December, averaging 132mm of precipitation across 11 rainy days. An umbrella or waterproof jacket is essential.
The rainy season in Smithtown runs through May, March, April, July, with the heaviest rainfall in May. Based on 10-year averages for Smithtown.
Smithtown receives approximately 105 sunshine hours per year. The sunniest month is July with around 12 hours. Based on climate data for Smithtown.
The least favorable months to visit Smithtown are January, February, March, December, primarily due to very cold temperatures, frequent rain. For the best conditions, consider June, August, September instead.
The annual average UV index in Smithtown is 5, classified as moderate. Standard sun protection (sunscreen, hat) is recommended during prolonged outdoor exposure.
Average humidity in Smithtown is 74%, classified as moderate. Humidity levels are generally comfortable and should not affect outdoor activities for most people.
Yes — sea temperatures in July, August, September average 23°C (73°F), which is warm and comfortable for swimming and water activities.
Yes, Smithtown receives snow. Months with snowfall average 4 snow days and 10 cm (4 in) of accumulation, with about 9 frost days during winter.
Average wind speeds in Smithtown are 25 km/h (16 mph). The windiest month is January with peak winds reaching 28 km/h (18 mph) (gusts up to 48 km/h / 30 mph).
Smithtown averages 5 clear-sky days per month with overall cloud cover around 57%. The clearest skies occur in October.
The annual average dew point in Smithtown is 8°C (46°F), which feels dry and comfortable. Outdoor activities are comfortable year-round from a humidity standpoint.
Smithtown has a Humid Subtropical climate, classified as Cfa under the Köppen system. Temperate climates have mild winters and warm summers, with rainfall spread across the year and four distinct seasons.
The 'feels like' temperature in Smithtown ranges from 7°C (45°F) to 14°C (57°F) on average. Wind chill makes winters feel noticeably colder than the actual temperature — layered clothing is recommended.
Yes, June is a great time to visit Smithtown. It earns a climate score of 8.8/10 with Excellent.
For June in Smithtown, pack Umbrella, Breathable clothing, Sunscreen (SPF 30+), Sun hat, Sunglasses. With average highs of 25°C (76°F) and 9 rainy days, these essentials will keep you comfortable.
Data Source
Climate data derived from ERA5 reanalysis (ECMWF), averaged over 2016–2025. Sea surface temperature from marine reanalysis data. Climate scores and seasonal estimates are computed by WorldStats.
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