The Chitwan National Park has
a tropical monsoon climate, with height humidity
all through the year, and three main seasons.
March to early June are the traditional hot
months, with temperatures rising progressively
to a peak in May. During April, despite the
heat of the day the nights can be quite cold.
South - westerly winds prevail, and relative
humidity is lowest in March.
Towards the end of May the pre-monsoon storms
set in. Dark clouds mass in the afternoons,
with thunder and lightning and high winds. If
rain falls, it comes in late afternoon showers
lasting perhaps only fifteen to twenty minutes.
As May changes into June the showers come with
When the monsoon proper begins,
around the middle of June, it is another story.
From then until late September the moisture-laden
south-easterly winds weeping up from the Bay
of Bengal bring heavy rain, and of the annual
total of some 80 inches, more than 80 per cent
falls in these three months.
Precipitation is not normally
continuous, and often, in any monsoon month,
there are as many dry days as wet ones. During
the monsoon humidity is extremely high.
Winter lasts from October to the end of February.
The northerly winds are cool, coming down from
the mountains, and this is the best time of
the year to see the Great Himalayan Range, the
air being particularly clear in November.
January is the coldest month,
with temperatures falling almost to freezing-point,
especially when it rains. From late November
the relative humidity touches 100 percent in
the mornings, and so there is dewfall during
December and January nights and sometimes when
you hear the drips pouring off the trees in
the morning, it is often mistaken for rain.
After an especially cold morning it is hard
to believe that the temperature will rise to
20-25 Celsius in the afternoon.