Heavy fog is defined as an observation with 1/4 mile visibility or less sometime during the day.
* = less than 1/2 day
For more information, click one of the following: Western States, Alaska, or Hawaii and Pacific Islands
MEAN MONTHLY AND ANNUAL NUMBER OF DAYS HEAVY FOG
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC ANNUAL
ALASKA
ANCHORAGE 6 4 2 1 * * * 1 1 2 4 5 26
ANNETTE 1 1 1 * 1 1 2 2 3 1 1 * 15
BARROW 2 1 1 3 7 10 12 12 5 3 2 1 61
BETHEL 4 3 4 4 5 3 4 6 5 4 4 5 50
BETTLES 1 * * * * * 1 1 1 1 * * 6
BIG DELTA 2 * * * * 0 * 1 2 1 1 1 9
COLD BAY 2 1 2 1 2 2 4 3 1 * 1 2 21
FAIRBANKS 4 2 1 * * * 1 2 1 2 1 3 18
GULKANA * 1 1 * * 0 1 2 3 4 3 2 18
HOMER 1 1 1 * * * 1 2 1 * * 1 8
JUNEAU 2 2 2 1 1 * * 1 3 3 3 2 21
KING SALMON 3 1 2 2 2 3 5 4 3 3 3 3 33
KODIAK 1 1 1 * 1 2 3 3 1 * * 1 14
KOTZEBUE 1 1 1 2 4 5 2 1 1 1 * 1 19
MCGRATH 2 1 1 * 1 * 1 1 1 1 1 2 13
NOME 2 1 1 1 3 4 3 1 1 * 1 2 21
ST. PAUL ISLAND 2 3 3 3 7 10 13 10 4 1 1 1 58
TALKEETNA * * * * * * * * 1 1 1 1 5
VALDEZ 1 1 1 * * * 3 5 3 1 1 1 17
YAKUTAT 2 3 2 2 2 3 4 5 4 1 1 2 29
ARIZONA
FLAGSTAFF 2 2 2 1 * 0 * * 1 1 1 2 12
PHOENIX 1 * * 0 0 0 0 0 0 0 * 1 1
TUCSON * * * 0 0 0 0 0 * 0 * * 1
WINSLOW 1 1 * * 0 0 0 0 * * 1 2 4
YUMA 1 * 0 0 0 0 0 0 * 0 * 1 2
CALIFORNIA
BAKERSFIELD 8 3 1 * * 0 * * * * 3 8 22
BISHOP * 0 0 * 0 0 0 0 0 0 * * *
BLUE CANYON 10 9 11 7 6 2 0 * 1 5 7 10 68
EUREKA 4 3 2 2 1 2 4 5 8 10 6 4 51
FRESNO 12 6 2 * * 0 0 * * 1 6 12 39
LONG BEACH 5 4 3 2 1 2 2 3 4 5 5 6 41
LOS ANGELES AP 4 3 3 2 1 1 2 2 3 5 5 5 37
LOS ANGELES CITY 2 2 1 1 1 1 1 1 1 3 2 2 17
MT SHASTA CITY 2 1 * * 0 * 0 0 * * 1 2 7
OAKLAND 4 2 1 * * 0 0 0 * 2 3 4 17
REDDING 5 1 1 * 0 0 0 0 0 * 2 6 15
RED BLUFF 6 2 1 * * 0 0 0 0 * 2 6 18
SACRAMENTO 10 5 2 * * 0 0 * * 1 5 10 34
SANDBERG 10 12 12 9 7 3 * 1 2 5 6 10 79
SAN DIEGO 3 3 2 1 1 1 1 1 2 3 3 4 23
SAN FRANCISCO AP 4 3 * * * * * * 1 1 2 3 14
SAN FRANCISCO CI
SANTA BARBARA 1 2 2 1 1 1 2 2 3 3 1 1 21
SANTA MARIA 5 4 5 6 6 7 8 10 12 12 7 6 87
STOCKTON 12 8 2 * * * 0 * * 2 8 11 42
COLORADO
ALAMOSA 4 2 1 1 1 * 1 1 1 1 2 4 19
COLORADO SPRINGS 2 3 3 2 2 1 1 1 2 2 2 2 22
DENVER 1 2 1 1 1 * * 1 1 1 1 1 10
GRAND JUNCTION 3 2 1 * * 0 0 0 0 * 1 2 8
PUEBLO 1 1 1 1 1 * * * 1 1 1 2 9
HAWAII & PACIFIC ISLANDS
HILO 0 0 0 0 0 0 0 0 0 0 0 0 0
HONOLULU 0 0 0 0 0 0 0 0 0 0 0 0 0
KAHULUI 0 0 0 0 0 0 0 0 0 0 0 0 0
LIHUE 0 0 0 0 0 0 0 0 0 0 0 0 0
GUAM 0 0 0 0 0 0 0 0 0 0 0 * *
JOHNSTON 0 0 0 0 0 0 0 0 0 0 0 0 0
KOROR 0 0 0 0 0 0 0 0 0 0 0 0 0
KWAJALEIN 0 0 0 0 0 0 0 0 0 0 0 0 0
MAJURO 0 0 0 0 0 0 0 0 0 0 0 0 0
PAGO PAGO 0 0 0 0 0 0 0 0 0 0 0 0 0
PONAPE 0 0 0 0 0 0 0 0 0 0 0 0 0
TRUK (CHUUK) 0 0 0 0 0 0 0 0 0 0 0 0 0
WAKE 0 0 0 0 0 0 0 0 0 0 0 0 0
YAP 0 0 0 0 0 0 0 0 0 0 0 0 0
IDAHO
BOISE 6 3 1 * * * 0 * * 1 3 6 20
LEWISTON 4 4 1 * * * 0 0 * 2 4 6 21
POCATELLO 5 3 2 1 * * * 0 * * 2 4 17
MONTANA
BILLINGS 2 2 2 3 1 1 * * 1 2 2 2 18
GLASGOW 2 2 2 1 * * * * * 1 2 3 13
GREAT FALLS 1 2 2 2 1 1 * * 1 1 2 1 13
HAVRE * 2 1 1 1 0 * * * 1 2 1 9
HELENA 2 1 1 * * * * * * 1 1 2 8
KALISPELL 5 5 2 1 1 1 1 1 2 5 5 5 33
MILES CITY 1 2 1 1 1 * * * 1 1 1 2 10
MISSOULA 5 4 1 * * * * * 1 3 5 6 27
NEVADA
ELKO 1 1 1 * * * * * * * 1 1 6
ELY * * * * * * * * * * * * 2
LAS VEGAS * * * 0 0 0 0 0 * * * * 1
RENO 2 1 * * * 0 * * * * 1 3 7
WINNEMUCCA 2 1 * * 0 * 0 0 0 * * 1 4
NEW MEXICO
ALBUQUERQUE 1 1 1 * * * * * * * 1 2 6
CLAYTON 1 1 2 1 1 1 1 * 1 1 1 1 12
ROSWELL 3 3 1 * * * * * 1 2 2 2 14
OREGON
ASTORIA 4 3 3 2 2 1 2 4 6 7 4 4 41
BURNS 4 2 1 * * * * * * * 1 4 12
EUGENE 9 7 4 2 1 1 * 1 4 11 10 10 60
MEACHAM 4 4 5 3 2 1 * * 1 2 4 4 31
MEDFORD 12 6 2 1 * * * * 1 4 11 14 49
PENDLETON 8 5 2 * * * 0 * * 1 6 9 31
PORTLAND 4 4 2 1 * * * * 3 7 6 5 33
SALEM 6 4 2 1 1 * * * 2 7 6 7 36
SEXTON SUMMIT 19 17 19 14 14 10 6 6 7 13 17 18 160
UTAH
MILFORD 1 1 1 * * 0 0 * * * 1 2 7
SALT LAKE CITY 4 2 * * * 0 0 0 0 * 1 4 12
WENDOVER 2 1 0 0 0 0 0 0 0 0 * 2 5
WASHINGTON
OLYMPIA 10 8 8 5 3 2 3 5 9 14 11 10 89
QUILLAYUTE 4 3 4 2 3 3 5 8 7 7 4 4 53
SEATTLE-TACOMA AP 5 4 2 1 1 1 2 3 5 7 5 6 41
SEATTLE URBAN SITE
SPOKANE 9 7 3 1 1 1 * * 1 4 9 12 48
STAMPEDE PASS 24 22 23 21 21 21 17 19 15 20 23 26 252
WALLA WALLA 3 2 * 0 * 0 0 0 * * 3 5 14
YAKIMA 5 2 1 * * 0 * 0 * 1 3 7 19
WYOMING
CASPER 1 1 1 1 1 * * * 1 1 1 1 9
CHEYENNE 1 2 3 3 3 2 1 1 2 2 2 1 24
LANDER 1 1 * * * * 0 * * * 1 1 4
SHERIDAN 1 1 1 * * * * * * 1 1 1 6