On average across the year, no, Luxembourg is not hotter than Marshall Islands . Luxembourg has an average temperature of 10°C/50°F and Marshall Islands has an average temperature of 29°C/84°F.
Luxembourg's hottest month is July, with an average maximum temperature of 23°C/73°F, which is not hotter than Marshall Islands's hottest month (January, with an average maximum temperature of 31°C/88°F).
On average across the year, yes, Luxembourg is colder than Marshall Islands . Luxembourg has an average minimum temperature of 7°C/45°F and Marshall Islands has an average minimum temperature of 26°C/79°F.
Luxembourg's coldest month is January, with an average minimum temperature of 0°C/32°F, which is colder than Marshall Islands's coldest month (also January, with an average minimum temperature of 26°C/79°F).
On average across the year, no, Luxembourg has less rain than Marshall Islands. Luxembourg has an average annual rainfall of 863mm and Marshall Islands has an average annual rainfall of 2364mm.
Luxembourg's wettest month is December, with an average monthly rainfall of 92mm, which is drier than Marshall Islands's wettest month (November, with an average monthly rainfall of 255mm).