Weather in New York in September

How September compares

September is the 4th warmest month of the year in New York and ranks 116th of 134 destinations we compare for September - see where else is hot in September. Within United States it is 6th of 6 (United States in September). Against London's average high of 18.6°C in September, New York is 5.1°C warmer by day and 4.6°C warmer at night.

Daytime and night-time in September

The typical September day in New York peaks at 23.7°C, but that is an average: the warmest 10% of days reach 28.4°C or more. Roughly 1 in 3 days top 25°C and 1 in 19 pass 30°C. Nights average 15.8°C; one night in ten drops to 11.4°C or lower, so pack a layer for evenings. Between 1991 and 2020 the hottest September day here reached 34.0°C (2010-09-01) and the coldest night 6.4°C (2000-09-29).

Rain in September

Wet (more than 8 rainy days): about 9 days with 1 mm or more, 98 mm in total. Year to year it varies a lot - the wettest September was 2018 with 278 mm, the driest 2005 with 15 mm. Humidity averages 74%.

Sea temperature in September

The sea averages 21.2°C - bracing (18-22°c). Depending on the year it ranges from 20.4°C to 22.2°C. For the warmest sea here, come in August (23.1°C).

Sunshine and daylight

Around 5.9 hours of sunshine a day (estimated from cloud cover), 12.2 hours of daylight: the sun rises about 06:37 and sets about 19:06 local time in mid-September. Average cloud cover is 52%.

Is September a good time to visit New York?

It is a reasonable choice: warm days but expect showers. The best months for New York on our scoring are August, July, June; months averaging 25°C or more: Jun, Jul, Aug.

Warm enough for light clothes, but pack a layer

September still has enough warmth to make a long day outdoors feel hot at times. Temperatures reach 25°C on 37% of days, while 30°C occurs on just 5%, so strong heat is possible rather than the norm. Humidity averages 74%, which can make warmer afternoons feel sticky; breathable clothing is more useful than a heavy jacket during the day. Keep your more energetic walking away from midday when it feels hot, and leave room for breaks. Evenings need a different approach: the coldest 10% of nights fall to 11.4°C or below. A jumper or light jacket gives you more flexibility than packing only summer clothes.

Plan for rain, not a washout

Rain is a meaningful part of the September trade-off, so take a waterproof layer and shoes you can comfortably walk in when pavements are wet. About 9 rainy days means you should allow for interruptions, but it does not mean those days will be wet throughout. Keep indoor plans flexible rather than committing every day to being outside. There is about 5.9 hours of sunshine within 12.2 hours of daylight, so daylight gives you more time to explore than the sunshine figure alone might suggest. This is a month for making use of dry spells, with a forecast check before deciding what to wear and how to spend the day.