I often read on the internet that the ideal range of relative humidity for a strand woven bamboo floor is between 30% and 60%. This advice is not very useful because it ignores the fact that relative humidity refers to what percentage of water vapor air contains compared to the maximum it can contain. This maximum value is measured in grams per cubic meter and is called absolute humidity. Thus at 15 degrees centigrade the absolute humidity is 13 grams of water per cubic meter. So if relative humidity is 100% that means the air contains 13 grams of water per cubic meter. However, if the temperature is 30 degrees centigrade the absolute humidity is 30.4 grams per cubic meter. Thus, if the relative humidity is only 50% the amount of water in the air is 15.2 grams per cubic meter.
Thus you can easily exceed a relative humidity of 60% and not have much water vapor in the air, and conversely you can be within the 30% to 60% relative humidity range and have water levels in the air which can damage your strand woven bamboo flooring.
To check the temperature, absolute and relative humidity levels use this link to go to a climate/humidity table.
Basically, the science is that the warmer the air the more water vapor it can hold. Warm air has more energy than colder air which allows water to remain in its gaseous state. When the absolute humidity reaches 100% and there is a temperature drop then the air can sustain less water as gas. This is the dew point - in other words the point where water vapor condenses and turns to water.
Strand woven bamboo flooring is a natural material that responds to changes in humidity. If there is a lot of water in the air then your strand woven bamboo flooring will absorb it and begin to swell over time and eventually warp and bulge. Conversely, if there is too little water in the air the strand woven bamboo will dry out and shrink causing cracking.
For people living in temperate climate zones in Europe neither scenario is very likely. However, for those who live in hot and sweaty climates the situation is different. The best thing to do is to turn on your air conditioner unit during really hot and sticky days. This sucks out the moisture from the air and protects your strand woven bamboo flooring. Alternatively, you can turn on the heating to raise the heat and thus the absolute humidity in the room to prevent water vapor condensing. Thirdly, just opening the windows and allowing a through breeze in the house draws off a lot of the condensing water vapor. Only really as a last resort is it necessary to buy a humidifier.
The opposite situation is when the air is too dry which can be the case during the winter months when people rely on heaters to stay warm. Space heaters and central heating dry out the air. To combat this you can again open the windows once in a while or you can leave a kettle boiling on a stove. The steam from the kettle will increase humidity levels in the room. If you are convinced that the air is still too dry and endangering your strand woven bamboo flooring then you can buy a humidifier that sprays water vapor into the air.