Is it bad to have my guests sitting in the sun?

Probably not a good idea however you could supply water for your guests and be on time for your ceremony :) 

I love the sun - but if you have guests not fond of the sun - find them a shady spot and a seat, if this is not possible pop them in side seats with a nice brolly (I have lovely brollies for this purpose....and rain). Most of my ceremonies go for around 15 minutes but if I need to factor in guest needs I can work around this time limit, or come up with an idea to make sure they enjoy your ceremony so you don't need to worry about them. As a person I am very caring to people's needs and I can always come up with an idea to ensure everyone is catered for. A nice tub with bottles of water and ice is a great idea for a wedding on a hot day - it's easy to find a guest who will help you out with this.

Well done for thinking about the well being of your guests so early on in the process. Ideally it would be best to have your guests sitting in the shade but that's not always feasible. February is hot in Australia, no matter where you are, but if you're in FNQ then you have the humidity to consider too. If possible, go to your location before hand, at the time you have chosen for your wedding, and see for yourself. If there is no shade then look at possibly hiring a gazebo or providing umbrellas, if you're budget allows. If it doesn't then there's no harm in asking guests to bring an umbrella along. It would appear that you have already provided seating (you mention 'sitting in the sun') but you could also provide water, either bottles in a tub or eski, or a water station set up in the shade with cups where the guests can help themselves. You could also provide fans. My only other suggestion is to ensure that your ceremony isn't too long.

Your guests are going to be there quite a while before you arrive but that does not mean that they have to be seated from the moment they arrive. A good celebrant will have a contact who is with the bride who will let them know when you are about to arrive. When they get their cue from the contact is when they will ask the guests to take their seats so that the guests will only be sitting just before and during the ceremony, thereby minimising the guests exposure to the sun and heat.

Yes, really bad form and can be a health risk

Your celebrant should be able to manage the day, keep the guests in the shade up until the last minute and then your guests will only have to be in the heat during the actual ceremony

You could also provide nice white umbrellas for your guests to use during the ceremony

You can provide a gazebo or ensure the venue has shady trees. Have a tub of cold bottled water for your guests.

The best way to keep your guests as cool as possible is to try and keep them under a tree if you are in a garden.  Otherwise a tub of ice with small bottles of water are a great alternative.  You can also buy inexpensive parasols from Bargin shops or on ebay if you are anticipating a warm wedding day.  This is particularly good for older guests.   

Try and avoid placing guests in the full sun.  If it can't be avoided, the celebrant will ask them to be seated at the last minute

February is usually one of the hottest months of the year.It would be ideal if you could provide some shade for you and your guests.Also avoid serving alcohol before the ceremony as this contributes to dehydration instead leave until after the ceremony and have bottles of water available for you and your guests.

If it’s really hot. Yes!  They may faint or at least sunburn. 

Its better to provide some shade if possible. 

Hello thanks for your question. February is a hot month for us.  I remember a summer wedding that I did, where the couple had made fan shaped coloured card, with information printed on them about the bride and groom.  Like how they first met, who was in their bridal party, how they know the bridal party ... just all very interesting little pieces to read on them. They were lovely keepsake and they worked well as a fan.

Also remember to have bottled water for them - especially for the two of you.  You could also hand out sun umbrellas as well ... maybe white ones, so that those feeling the heat can use them.  Gazebo is also a good idea.

However this February is supposed to be particularly hot.  You really don't want anyone to be sick or heatstruck, so perhaps you do need to think about a plan B if it is too hot.  Just like you would if it was raining.  All the best!