Bad news... both of those periods are when the 'wet' comes. However, that doesn't discount safari as if rain, rarely daily, all day or even if. Should it rain, often a brief amazing thunderstorm during daytime, or showers overnight or mornings. But know that many do travel during these periods as prices are 'low' (Apr/May) and 'mid' (Nov/Dec)... often less vehicles/tourists... but the game is always there as they don't go on holiday.

However, right now in Jan and likely going into Feb which is usually considered the 'dry' period, it's been raining many places often leaving no roads, rivers turned into lakes, mud everywhere and vehicles getting stuck, airstrips unusable. Hey, it's weather! No one can know from month to month, much like your weatherperson at home is often wrong.

On my many visits during Nov/Dec when rain would be expects, we had none or maybe a shower; this year Oct/Nov, there were clouds almost daily and wet sometime during each day though we did manage to drive far enought away to miss it on some.

Water is needed in Africa... it's precious, for crops, filling up the resevoirs... so I go just with the flow and be prepared for whatever.

Can't say how it would be in Uganda or Rwanda, but makes sense if it's wet, the treks to find the gorillas will be quite slippery.

Like Sandi said, both of these periods are technically the "rainy" season. I've experienced both very wet and very dry Nov/Dec periods so you never know. On the plus side, prices are lower and there will be fewer people. Some camps do close during these times but there are still plenty that are open.

Here are some reports from some of the timeframes you are considering

http://www.fodors.com/community/africa-the-middle-east/ohmigosh-back-on-safari-with-micato---trip-report---may-2007.cfm

http://www.fodors.com/community/africa-the-middle-east/kenya-tanzania-trip-report-172191-2.cfm


http://www.fodors.com/community/africa-the-middle-east/patty-marks-2006-kenya-tanzania-report.cfm

http://www.fodors.com/community/africa-the-middle-east/kenya-and-tanzania-safari-november-2009-trip-report.cfm

http://www.fodors.com/community/africa-the-middle-east/november-tanzania-safari-recommendations.cfm

http://www.fodors.com/community/africa-the-middle-east/just-back-from-tanzania-184155-2.cfm

http://www.fodors.com/community/africa-the-middle-east/photos-and-trip-report-tanzania-april-2006.cfm




Discussion about time frame you are considering
http://www.fodors.com/community/africa-the-middle-east/help-with-kenya-tanzania---april-07.cfm


http://www.fodors.com/community/africa-the-middle-east/november-safari-kenyatanzania.cfm

http://www.fodors.com/community/africa-the-middle-east/kenyatanzania-august-vs-november-tradeoffs.cfm

Hello,
We travelled to Kenya and Tanzania this past May, for the month. I couldn't have found it any nicer. The plains were so green, with flowers blooming, and loads of animals. We had so little rain, we couldn't call it the rainy season. The prices were so much better than even from 1 month later. I would recommend May, from our experience. Happy planning. You are in for a wonderful experience whenever you decide to go.

I'd like to thank fodorites for their replies and help on both my recent threads.

I will look at the various threads suggested by atravelynn and get working on the logistics of the trip.

Hi
it would be dificult to predict how much rain you will see during you trip but in Tanzania around midt november there is a good chance for:_ verry hot weather
_ either verry dry or small pockets of green bush and still quite little surface water available, witch is meaning great consentration of wildlife around waterholes (this changing normaly around december)
_most wildlife inactive during the day heat.
_ low grass, quite open bush...
_longers days
_lots off impalas lambs
_generaly healty meat eaters...
_ if rainning spectaculars insect eclosions and activity

in May: _Coulder weather, espesialy early in the morning
_green bush with a lot of surface water available and wildlife spread around
_wildlife more active during the day
_shorter days

_high grass, denser bush...
_healty plants eaters...

Note that in the short grass area of the serengeti there is less prey animals available to the predators in november. The migrations animals arriving generaly around december-january there...

Anyway being in the african bush is always rewarding, at any time of the year...
a few more hints for november-december: fantastic smell off the first rains on the dry ground...
verry larges prides of lions...swifts chasing termites...spectaculars thunderstorms...
May: Misty mornings... great elephants sighseings...

While you're taking time to review lots of threads, RJames, I'll be humming Super Freak to myself. Your name put that song into my head.

When it comes to weather and other experiences, I always hesitate to rely on the personal experience of one or two people who might have gotten lucky or unlucky. I prefer to rely on statitical probability based on past weather trends. Also, it is good to know about what animals are likely to be in what areas at what times.

I happen to love this chart which includes average high and low temps as well as animal types, though it is missing rhinos for some reason. Also, it doesn't give average rainfail or sunrise / sunset times but you can supplement that information on www.weather.com with historical averages. They have charts that go day by day, so for example, you compare early November with late November.

Oops...forgot the link to the chart which is found on the website for Africa Adventures. Here you go:

http://www.africa-adventure.com/best_time_to_go