Weather

From the tourism website for Alice Springs:

The climate of Alice Springs in Australia's Red Centre is one of extremes, with hot summers and cold winters. Plan ahead with this information on temperature and rainfall.

Summer (December – February)
In summer average temperatures range from 20 - 35°C (60 - 95°F), and can soar to around 40°C (104°F). January is the wettest month with around 40mm (1.5") of rainfall, however the climate is considered dry and arid for most of the year.

Autumn (March – May)
Autumn is one of the best times to visit Alice Springs, with warm days and cool nights. Average temperatures range from 12 - 27°C (53.6 - 80.6°F).

Winter (June – August)
During winter, average temperatures fall between 4.8 - 20°C (40.6 - 68°F), with July being the coolest month. Nighttime temperatures can drop below 0°C (32°F) and thick frost on the ground can resemble a carpet of snow.

Spring (September – November)
In spring the weather begins to warm up with average temperatures between 13.8 - 30.6°C (56.8 - 87°F). It can bring spectacular thunderstorms and cool evenings.

From the tourism website for Uluru:

Uluru is situated near the centre of a semi-arid desert, Temperatures can range from 3.5° C in July to 37.5° C in January. On average Uluru-Kata Tjuta receives approximately 308mm (12 inches) per year, so not much at all.

Temperature
The climate in this region is extreme. In winter, daytime temperatures can be pleasant but clear nights can see the temperature drop below 0. In summer on the other hand, the temperature can get very hot peaking as high as 45C. Normally its around 30 -35C.

The highest temperature recorded at Uluru was 45.5°C (114°F) on 17 February 1992 and that was in the shade! Lowest temperature recorded was minus 4°C (25°F) in July 2001 (on a winter's night) and in 1997 it actually snowed on Uluru.

Rainfall
Uluru-Kata Tjuta averages 308mm (about 12 inches) rain each year. It typically has 5 days a month all year round when it is cloudy (not necessarily raining) so you would have to be lucky to actually be there when it rains.

Other 
If you are travelling between May and October make sure you pack the appropriate clothes. Nights and mornings can get quite cold, so it is important that you have warm clothes packed especially if you are planning any sunset or sunrise activities. Unlike Darwin and the Northern part of Australia which has a wet and dry season. Uluru is accessible and a great place to visit year round.

Local Aboriginal people recognise five seasons:

1. Wanitjunkupai (April/May) – Cooler weather
2. Wari (June/July) – Cold season bringing morning frosts
3. Piriyakutu (August/September/October) – Animals breed and food plants flower
4. Mai Wiyaringkupai (November/December) – The hot season when food becomes scarce
5. Itjanu (January/February/March) – Sporadic storms can roll in suddenly