The climate of Pattaya is tropical, hot all year round, with a dry season from December to April, and a rainy season from May to mid-November, due to the southwest monsoon. The annual precipitation amounts to about 1,100 millimetres (44 inches), so the rains are not that heavy, if not in the first phase (May) and the last (September-October): this is because the bulk of the rains is released on the Burmese west coast, which therefore protects this area of Thailand. However, some strong downpours can not be excluded also from June to August, although in this period, rainfall remains on average around 95/120 mm (3.7/4.7 in) per month.
In March and April, before the monsoon arrives, there can be a certain increase in rainfall, although the sunshine amount is still good.
Here is the average precipitation.
Average precipitation - Pattaya

Pattaya	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Year
Pattaya	J	F	M	A	M	J	J	A	S	O	N	D	Y
Prec. (mm)	15	15	55	65	150	120	95	100	205	215	70	10	1115
Prec. (in)	0.6	0.6	2.2	2.6	5.9	4.7	3.7	3.9	8.1	8.5	2.8	0.4	43.9
Days	1	3	4	6	12	11	11	12	17	18	10	1	106

The period before the monsoon, from mid-February to May, is also the hottest of the year: the maximum temperature can reach 34/35 °C (93/95 °F), and the minimum around 28 °C (82 °F). Luckily the breeze tempers the heat. On the contrary, in winter, from December to mid-February, sometimes it can get a bit cool, so that lows can drop below 20 °C (68 °F), and highs can remain around 24/25 °C (75/77 °F).
Here are the average temperatures.
Average temperatures - Pattaya

Pattaya	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Pattaya	J	F	M	A	M	J	J	A	S	O	N	D
Min (°C)	23	24	25	26	27	27	26	26	25	24	23	22
Max (°C)	31	31	32	33	32	32	31	31	31	31	30	30
Min (°F)	73	75	77	79	81	81	79	79	77	75	73	72
Max (°F)	88	88	90	91	90	90	88	88	88	88	86	86

The amount of sunshine in Pattaya is good from December to April, the dry period, while it is not very good from May to September, in the monsoon period, when the sky can remain cloudy for several hours.
Sunshine - Pattaya

Pattaya	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Pattaya	J	F	M	A	M	J	J	A	S	O	N	D
Sun (hours)	7	8	8	7	5	4	4	4	4	5	6	7

Pattaya can be reached by tropical cyclones, in particular from typhoons, which come from the east, normally from June to December (although they are more frequent from September to November), and generally affect more directly the interior of Thailand, but sometimes they can also enter the Gulf of Thailand.



For swimming, the sea is warm all year round, as you can see in the following table.
Sea temperature - Pattaya

Pattaya	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Pattaya	J	F	M	A	M	J	J	A	S	O	N	D
Sea (°C)	28	28	29	30	30	30	29	29	29	29	29	28
Sea (°F)	82	82	84	86	86	86	84	84	84	84	84	82

The best time to go to Pattaya goes from December to April, that is, in the dry season, with a preference for the period December to mid-February, because from mid-February to April there is an increase in temperature. From December to February you can bring a sweatshirt for any cool evenings.
If you want to go in summer, in July and August, you will have to cope with a sultry heat, increased cloudiness, some showers, sometimes strong, and the risk of a tropical storm or cyclone. However, depending on year and period, the weather can be decent or good for weeks in these months as well.