Weather in United States in January

January climate overview

Daytime highs across United States in January run from 3.2°C (New York) to 24.5°C (Hawaii). Even in Hawaii only 36% of days reach 25°C. Nights average 10.7°C; the coldest 10% of nights in New York fall to -12°C or below.

Rainfall in January

Expect around 7 rainy days (1 mm or more) in January, with Las Vegas the driest (4 days) and New York the wettest (9 days). The wettest January at Hawaii between 1991 and 2020 was 2004 with 149 mm; the driest was 2017 with 3 mm.

Sea temperature

The sea averages 19.3°C around United States in January - warmest at Hawaii (24.5°C). That is bracing: fine for a dip, cool for long swims.

Sunshine and daylight

Around 5.3 hours of sunshine a day on average, out of 10.8 hours of daylight (sunshine estimated from cloud cover).

January against the rest of the year in United States

January is the 12th warmest month of the twelve in United States. It is 1.0°C cooler than December and 1.2°C warmer in February. The hottest month here is July (31°C) and the coolest January (18°C).

Which part of United States in January?

• Most sunshine: Hawaii, 6.5 h a day.
• Driest: Las Vegas, about 4 rainy days.
• Warmest sea: Hawaii, 25°C.
• Hottest: Hawaii, 25°C by day.
• Coolest (better for walking and cities): New York, 3°C.

What to pack for United States in January

Based on the averages: proper layers and a jacket - daytime highs average only 18°C; a warm layer for evenings, when it drops to around 11°C; a light waterproof for the odd shower; swimwear if you do not mind a bracing 19°C sea.

Similar weather elsewhere in January

Within 1.5°C of United States's January daytime average: Fuerteventura (19°C, sea 19°C), Hong Kong (19°C, sea 19°C), Lanzarote (18°C, sea 19°C), Marrakech (18°C), La Palma (17°C, sea 20°C). See the full ranking for January.

Hawaii and Florida for winter warmth

Hawaii suits travellers who want warmth that lasts into the evening: nights average 21°C, so there is less need to wrap up after sunset. Miami stays mild at night too, averaging 18°C, while the wider Florida average falls to 15°C. Orlando has a more noticeable change between day and night, dropping from 21°C to 11°C, so bring a jumper or light jacket alongside daytime clothing. The catch is that January warmth is not guaranteed heat. Even in Hawaii, the share of days above 25°C is 36%. Plan for comfortable outdoor weather rather than assuming every afternoon will feel hot.

Las Vegas and New York need a different wardrobe

Las Vegas is better suited to travellers who prefer mild daytime weather over beach heat. Its 14°C daytime average makes layers useful, and nights at 4°C call for a warm jacket rather than just a light cover-up. New York is a proper winter choice: daytime temperatures average 3°C and nights fall to -5°C. Take a warm coat, gloves and footwear you can comfortably wear in the cold, and leave room for indoor breaks during outdoor plans. Neither destination makes sense if warmth is the main aim. They suit travellers happy to dress for the weather, especially when heading out after dark.

Allow for rain and keep outdoor plans flexible

January is not reliably dry across these destinations. Miami averages 8 rainy days, while Hawaii and Florida each average 7, so warm weather does not remove the need for a waterproof layer. Orlando is a little lower at 6 rainy days; Las Vegas has 4, making it the drier choice here, though not the warmer one. New York averages 9 rainy days, so cold is not the only consideration when packing. With average sunshine of 5.3 hours across the destinations, avoid building the whole holiday around uninterrupted sun. Keep outdoor plans flexible and use the warmer part of the day for longer spells outside.