We're not saying it's an exhaustive list but they're ones we're aware of and we've seen the issues caused by most of them too.
A deluge of rain suddenly as your patrons queue to enter your event will change their mood and yours very quickly.
In good weather, you often find that your audience will arrive earlier.
In heavy rain they're likely to arrive closer to the stage time for the main act, for instance.
Both instances have an impact on your management, staffing lessons, entry processing time etc.
Weather, be it scorching sunshine or incessant downpours, can significantly affect the arrival profile of your audience.
Greenfield sites can often experience significant issues with the wind swirling and impacting the sound quality.
Consider the prevailing wind when you're deciding where to locate your stages, tents & structures. Also establish the wind rating for those elements and ensure you monitor the wind in the run up to and during your event.
Also consider where the sun will be setting and whether it might affect the audience's enjoyment if, for instance, it sets behind your stage as your main act are on.
Weather pushing towards either end of the spectrum, good or bad, will result in your medical facilities being busier than otherwise.
In hot weather, dehydration, sunburn and people passing out from the heat are quite common.
In very wet weather hypothermia and pneumonia can become serious issues.
Water is always popular, particularly at outdoor concert / festival events but in hot weather you'll find it all the more popular.
Weather on either end of the spectrum can have a significant impact on your staff both from a morale and performance perspective.
You don't wanted a drowned-rat steward being your event-goer's sole interaction with you event, for instance.
This can affect both people and vehicles.
We've worked on events where the ground had become so muddy that the site vehicles spent more time pulling patrons' cars out of the fields than doing actual site work.
Just last year, I worked at Glastonbury and the heavy rain during the week made for some extremely challenging and muddy conditions for people walking through the site.
The likes of rain, fog, snow, ice, thunder, lightning and even volcanic ash clouds can cause havoc with your acts trying to get to your festival or event.
The skies over Europe were practically empty for a period in 2010 when a volcano erupted, spewing ash into the atmosphere.
Where you get heavy rain, you get umbrellas.
Where you get umbrellas you can get people's views of stages and acts being blocked, people around the umbrella actually getting wetter and you can see them used as weapons.
IF you have people arriving to your event in the rain, then they'll likely bring the wetness inside with them and this can make floors indoor extremely slippy.
People are affected by the weather. Good weather helps us keep a good mood while in bad weather we're more likely to do stupid things.
The use of pyrotechnics can depend heavily on the wind direction and strength. While it may not feel 'windy' to you and I it could well be windy enough to dangerously impact the pyro and where the fallout zone will actually be.
Restocking and vendor deliveries can be seriously impacted by weather. In the worst case scenarios you can find yourself in a situation where they can't get through to site.
At festivals and events it can often be the case that a large amount of the staff could be working in a casual capacity and, as such, can quite quickly decide not to bother showing up for a shift if it's too hot or too wet.
This can obviously cause your event significant issue as your staffing levels won't be what they should be if this happens.
We've worked at festivals where flooding became a serious issue, to the point that we had to send staff to check on tents to ensure people weren't asleep / passed out in them.
It's important to keep this in mind if you've got very heavy rain and a camping festival.
I've worked a festival in Ireland, believe it or not, where dust became a major issue. It made staff and attendees extremely uncomfortable and impacted EVERYONE'S moods.
Weather is one of those things you have NO control over but that you need to pay LOADS of attention to.
It's got the capacity to cause significant issue up to and including shutting you down.