If you’re hoping to get lost in the rain on your romantic getaway, take a look at these details about year-round temperatures in Lauterbrunnen: The hottest months are usually July and August, with an average temperature of 12°C, while the coldest months are January and February, with an average of -4°C. The rainiest months in Lauterbrunnen are July, June, August and May, with each month seeing an average of 221 mm of rainfall.