Marymac
Not sure TBH I went in October and it was VERY HUMID and VERY HOT...have a look at the weather on internet to see if you can find out rough temp..when I went it was shorts as in 3/4 type, vest top and overshirt,there is not much room in the jeeps so when your on the game drives it is JUST what you really need, ie, drinking water, wet wipes, or hand cleansing gel stuff as you do get quite sweaty!!!!, lip salve, lips can get very dry, if you have long hair? as the windows and roof are open something to tie your hair back as it gets blown around, sun hat? and most import a CAMERA, maybe a few sweeties to suck,nothing to sticky. we found that on the game drives you and the clothes do get covered in the orange dust/earth, so really you might get away with the shorts another trip but the tops can get mucky. Also keep the colours nutral there is a reason safari clothes are beige/green...DO NOT wear BRIGHT!!!! yellows oranges pink or you will be covered in insects..I just bought a couple of the crnikle overshirts lightweight and cheap.
You have a fantastic trip ahead of you enjoy
Cindy