February is one of the 'summer' months, so it's not unusual for daytime temps on the mainland for safari to reach into the 90s, though mostly dry (except for hotels in Arusha that have a/c, not so when out on safari though mornings/nights are cooler... maybe by 15-20 degrees. Zanzibar though is tropical where daytime temps can easily go into the 100s, and definitely humid. This is peak season for many wishing to get away from the nasty/cold on the Continent or from North America... so prices will match.

Yes, the calving takes place during this time and even cat cubs can be born, though the latter are also born year-round. When it comes to safari, what you see from day-to-day or area-to-area is never a guarantee, but you can be assured of seeing more than imagined. Also know that because of the calving, it's the busiest time and even at this late date many lodges/camps are fully booked... though you might get lucky.

On Zanzibar, I would highly recommend a place that has air conditioning vs only ceiling fans.

Suggest you contact a tour operator or in-country outfitter as soon as, to determine what is available and how it works with your estimated budget.

And, if you haven't done so yet... check to see what international flights are available and costs.

Thanks very much for your reply, Sandi.
We've got feelers out to some tour operators with availability, including OAT.
We weren't planning to go to Zanzibar because of the heat and humidity.
Another question - In case we come in a day early to Arusha to get over the long flight, what would you suggest doing for an easy few hours in town?
Thanks.

Your first day on the OAT trip is fairly laid back... cultural and shopping activities. If you arrive early, you could go to Arusha NP on a day trip and start your wildlife viewing early. Or, head out to the Cultural Centre for some shopping.

Temperatures can really fluctuate in February. When I was Tanzania in February 2005, it was over 100 degrees some days. Then, a series of thunderstorms came through and broke the heat wave. Like anywhere else, the actual temperatures will most likely vary from the averages.

We did get to Tanzania in February, with OAT. We did the pre-trip to the Kilimanjaro area, but not to Zanzibar.
We had a wonderful experience and enjoyed the country and its people very much.
The weather was fine. We had a bit of rain a few times, either at night or only for about half an hour during the day.
The only time it was very hot - say about the mid-90s - was on about a third of the days for an hour or two in the afternoon.
We did bring along packets of electrolytes which we used a few times.

Nail
On the OAT Trip did you spend a lot of time driving from place to place? We're the lodges inside or outside the game areas? How many people with you? What kind of vehicles? Any specific info would be great