Scales are tricky - for weight loss and weight GAIN!

In February this year I recorded my measurements and weight. I happened to find that record today (on my iPhone) and compared with my current weight and measurements. Since Feb I have put approx 2inches on my hips and waist and 1.5 inches on my thighs - not good. Interestingly I am exactly the same weight! So if I just looked at the scales they would mislead me to believe that I wasn't putting on weight when my measurements tell a different story. Another reason to get out that measuring tape!!! By the way of anyone can explain this mystery I welcome your response!