Weather and Climate
Spring can sometimes bring high winds, especially in the afternoon. Temperatures may vary widely: highs may reach into the 60s F, or only into the 30s F with an even colder windchill. Lows can also vary from 0 degrees F to the 30s F. March and April are the snowiest months of the year, but some days, especially in later spring when Medano Creek is flowing, can also be swimsuit weather.
In summer, daytime air temperatures average in the 70s-80s F. However, sand surface temperatures can soar to 140 degrees F on sunny summer afternoons. Summer nights are surprisingly cool, thanks to our elevation of 8200' above sea level. Even in summer, warm layered clothing is recommended, as lows may drop into the 40s. After dark, a warm coat or a blanket are necessities. Afternoon thundershowers are common in July and August with associated winds and lightning. Be prepared to leave the dunes promptly if thunderstorms threaten: lightning strikes are common and can be fatal.
Fall is generally mild, with Indian summer days. Highs average in the 60s - 70s F, with chilly nights in the 20s - 30s F. Be prepared, though, for the occasional cold fall storm, bringing icy rain or even snow.
Cold temperatures are the norm in winter, even though sunshine is generally abundant. The lowest temperature recorded at Great Sand Dunes was minus 25 degrees in 1963. Average highs are in the 20s-40s F, with lows averaging minus 5 degrees F below zero to 15 degrees F above zero. Snow may fall and high winds may occasionally occur, so bring warm, layered clothing and sturdy footwear.