Alaska is the largest state in the United States, boasting vast areas and diverse climate zones.

From Arctic climates to maritime climates, Alaska exhibits unique rainfall patterns in each region.

This blog post will provide detailed information on the annual average number of rainy days, precipitation, record rainfall, and regional climate characteristics across Alaska.

Annual Average Number of Rainy Days

The annual average number of rainy days in Alaska varies significantly by region. Overall, Alaska has areas that receive relatively high and low amounts of rain.

  • Western Coast (especially Anchorage and Juneau): An average of about 150 days of rain per year. This area has a maritime climate, characterized by high rainfall and frequent rain.
  • Interior (Fairbanks): An average of about 50 days of rain per year. The interior has a continental climate, with very cold and dry winters.
  • Eastern Alaska (including Delta Junction): An average of over 130 days of rain per year. This area also has a maritime climate, with significant rainfall.
  • Northern Alaska: An average of about 60 days of rain per year. This region has a polar climate, with more snowfall than rain.

Monthly Average Precipitation

The monthly average precipitation in Alaska varies greatly by region. Here are the averages for major cities:

Anchorage

  • January: About 2.0 inches of rain.
  • February: About 2.1 inches of rain.
  • March: About 3.0 inches of rain.
  • April: About 2.5 inches of rain.
  • May: About 3.5 inches of rain.
  • June: About 3.8 inches of rain.
  • July: About 3.5 inches of rain.
  • August: About 3.3 inches of rain.
  • September: About 3.0 inches of rain.
  • October: About 3.2 inches of rain.
  • November: About 3.1 inches of rain.
  • December: About 2.5 inches of rain.

Main Features:

  • Spring (March to May): Spring sees a gradual increase in rainfall, with melting snow contributing to significant rain.
  • Summer (June to August): Summer is the wettest season in Alaska, characterized by humid conditions and frequent rain.
  • Autumn (September to November): Autumn still sees considerable rainfall, but precipitation gradually decreases as winter approaches.
  • Winter (December to February): Winter has relatively low rainfall, but it is a time of heavy snowfall.

Fairbanks

  • January: About 0.7 inches of rain.
  • February: About 0.6 inches of rain.
  • March: About 1.2 inches of rain.
  • April: About 1.0 inch of rain.
  • May: About 1.8 inches of rain.
  • June: About 2.0 inches of rain.
  • July: About 1.9 inches of rain.
  • August: About 1.7 inches of rain.
  • September: About 1.3 inches of rain.
  • October: About 1.0 inch of rain.
  • November: About 0.9 inches of rain.
  • December: About 0.7 inches of rain.

Main Features:

  • Spring (March to May): Spring is relatively dry, with increasing rainfall but still less than summer.
  • Summer (June to August): Summer is the wettest season, with persistent humid conditions.
  • Autumn (September to November): Autumn also sees rain, but it gradually decreases as winter approaches.
  • Winter (December to February): Winter is very dry and cold, but heavy snowfall occurs.

Record Rainfall

The highest recorded rainfall in Alaska varies by region, but the highest recorded rainfall in Anchorage occurred during a downpour on July 1, 1989, with 13 inches (about 330mm) of rain. This rainfall resulted from a concentrated downpour over a short period, causing flooding and inundation in the area.

Main Impacts:

  • Flooding: Roads and homes were flooded, leading to traffic disruptions and property damage.
  • Infrastructure Damage: The sewer system and other urban infrastructure suffered significant damage, requiring a long recovery period.
  • Casualties: Several casualties were reported due to incidents related to flooding caused by the rainfall.

Regional Climate Characteristics

Alaska's vast area and diverse terrain result in significant climate variations by region.

  • Western Coast: Primarily maritime climate, with significant rainfall throughout the year. Frequent rain contributes to lush greenery and a humid environment.
  • Interior: Continental climate, with hot, dry summers and very cold, dry winters. Snowfall is more common than rain.
  • Eastern Alaska: Maritime climate, with significant rainfall and a humid environment. Heavy rain from hurricanes and thunderstorms is frequent in summer.
  • Northern Alaska: Polar climate, with more snowfall than rain, and very cold, long winters.