Besides the weather, are there any special considerations, preparations, dispensations, etc. that are required for having Eucharistic adoration outdoors?
Normally, a canopy must cover the Blessed Sacrament, i.e something must cover the top of it to protect it from any possible weather changes.
This could be anything from a tent over an adoration altar, to a processional canopy to an umbrella.
Have a procession beforehand! They are awesome for devotion to Our Lord!