Summer(June, July, August) is the big season in Cat Ba as well as a good time to cruise but the best time of year is during autumn and spring.
Cat Ba’s climate is humid and tropical. With a hot, humid summer and dry, cold winter, Cat Ba’s temperature varies from 15ºC to 28ºC, up to 35ºC in Summer and below 10ºC at times. The average humidity is 85% Annual rainfall is about 1700mm-1800mm. Cat Ba has typical diurnal tide system (tide amplitude ranges from 3.3-3,9m).
The salinity is 0,930% in Summer, 3,111% in Winter. It is possible to visit Cat Ba year-round, with the best time from late September through April, although during the winter months of December, January and February, the weather can be chilly and overcast with low visibility. From early April to September, temperature increases with heavy rains and storms
March, April, May: Temperature:20ºC-26ºC; light rains sometime; Clear with blue sky
June, July, Aug: Temperature: 26 ºC -35 ºC; Busy season; Heavy rains but quick. Check the Typhoon forecast before travelling.
Sept, Oct, Nov: Best time to enjoy Cat Ba and Ha Long with cool temperature: 26 ºC-28 ºC
Dec, Jan, Feb: Temperature:15 ºC-20 ºC; Cold with monsoon; foggy and drizzling
