Spanning the breadth of the North American continent, the USA has a very varied climate.
In general, give yourself flexibility by taking lots of light layers of clothing with you, plus a good jacket and waterproofs for the winter or for areas at high altitude. Good walking boots or shoes are always recommended and in summer a wide-brimmed sun hat and a high factor sun screen (at least factor 25, but preferably above) are musts.
The weather is a key part to planning any holiday, so below is the climate information that you can expect to find during your trip to the US. We have focused on the four main areas visited by members on our motorhome touring holidays. You can also find more information at the USA Today website and the Weather Channel website.
Alaska – general
South-central Alaska, including Anchorage and Prince William Sound, enjoys temperatures kept mild by the Gulf of Alaska, with north polar winds being largely blocked by the mountains. It tends to be brighter and colder than south-east Alaska, which is milder and gets more rain. Winters are very snowy indeed (7.5 metres along Prince William Sound), so spring and summer are when to visit, with the coast usually clear of snow from early May until mid or late September.
Alaska – daylight
Its northerly location means Anchorage gets 19.5 hours of daylight at the summer solstice. If you are a light sleeper you may wish to take eye pads and ear plugs, to keep out the sunlight and birdsong during your normal sleeping hours.
For more information please see Alaska.com.
California and the west (including Colorado, Utah and Nevada).
California has warm or hot weather all year, being warmer in the south. There are several winter resorts in the midland mountains of California. Many of the mountains and uplands of Colorado, Utah and Nevada are ski areas in winter, while in summer the climate is generally very hot and dry, compared to the humidity sometimes experienced on the California coast.
Light clothes are appropriate in summer, although nights may be cool, or possibly even a little chilly at altitude. In winter, costal California is usually mild, but the inland western states may be a lot colder, with snow and ice common in some parts.
Hiking in the desert should be supported by copious supplies (several litres if necessary) of water. At the bottom of the Grand Canyon in August, temperatures commonly reach between 40ºC and 50ºC during the afternoon, so a hike down and back from Grand Canyon village should include two early starts, an afternoon break in the shade and a night at the Indian Garden campground. Wherever you are, always take local expert advice before hiking.
Known as the sunshine state, its location on the Gulf of Mexico means that Florida enjoys long, hot and fairly humid summers. Winters are mild with occasionally cool or sometimes cold air. Temperatures inland are slightly higher in summer and slightly lower in winter than they are on the coast.
Spring can be delightfully cool in the evening and warm and bright during the day, but locals make plenty of jokes about how brief this period can be. Despite a northerly, coastal location, summer can be hot and may also be quite humid, with temperatures sometimes capable of reaching 30°C-40°C.
Autumn (Fall) is still warm and pleasant, with nights not uncomfortably a little chilly. This is the most popular time to visit, with many people coming to see the spectacular fall foliage colours. Hiking, cycling and canoeing are comfortable and popular pursuits at this time of year. By Thanksgiving Day (the fourth Thursday in November), the ski season is approaching.
For more information please visit the New England Travel Planner website.
Severe weather and natural phenomena
Keep an eye on local weather reports, particularly if travelling in areas known for extreme weather (such as snow in the mountains, tornadoes in the mid-west, hurricanes on the Gulf of Mexico or even carrying over to the east coast).
The hurricane season is normally June-November. The US Geological Survey (USGS) and other sources rate as high the probability of at least one earthquake, of at least 6.7 magnitude (enough to cause widespread damage), striking the west coast (including Alaska and Hawaii) by 2032. See also the Earthquake Hazards Program website.
Forest and bush fires are particularly prevalent from March to November, in dry, windy weather and on the west coast. Keep an eye on regional news reports.