Most save the date cards will not require more than a typical forever stamp (first class) when you are mailing with the US postal service, because they are usually fairly small (5x3.5 inches, 5.5x4.25 inches) and will weigh under an ounce.
Day by Day weather log for Barcelona Weather in September. September 30. Daily Comment: Temperature 25Â° C around 77 F Warm and sunny light cloud at times but generally clear skies. Day 29. Daily Comment: Temperature 25Â° C around 77 F warm and sunny. A little light cloud at times from 15:00 onwards.
Guide to Spain weather in May.  The average maximum daytime temperature in Spain in May is a warm 22Â°C (72Â°F). The average night-time temperature is usually a cool 9Â°C (48Â°F). There are usually 9 hours of bright sunshine each day, which represents 59% of the 14 hours of daylight.