That depends on the specific desert. Antarctica would be best in the summer. Hot deserts might be cooler in the winter. Cold winter deserts would be best in fall or spring.
The summer months are the best months to avoid the desert.
The best time to visit Chili is between March and June. The weather is said to be perfect during that time of year.
The best time to visit Orlanda is usually in October or November, the crowds aren't as bad and the weather is still nice.
The best time to visit the Canary Islands is during the spring. The summer is also a good time, with the hot summer weather, but it will be busier that time of year.
Anytime around July is nice...
The best time to visit Machu Picchu is between February and October because the weather is drier during the South American winter months.
Usually, the best weather is at the end of June and the Beginning of July. The British weather is a little temperamental, so it is impossible to give any guarantees.
Huatulco is located on the Pacific coast in the Mexican state of Oaxaca. The best time of the year to visit depends on the reason for your visit. The rainy season is from June to November so if your looking for the best weather then you should visit between December and May.
"The best time to visit the Dallas Aboretum is pretty much any time you are in town. Dallas has great weather year round, so it would never really be a bad time."
The Burren has such a variety of flora and fauna, that any time of the year will have things of interest to see. Like anywhere, good weather makes places nicer to visit, and the best weather in Ireland is during the summer months. If you are just a general tourist, then that would be the best time. If you are visiting for more specialised reasons, then why you are visiting will influence what time of the year you want to visit.
I would go to Florida in the spring or early summer.
The summer in Fiji occurs from December to March. For this reason, many people like to visit from May to early October for the best warm weather.