Alert archive / California / Dense Fog Advisories

Dense Fog Advisories in California, 2021

141 dense fog advisories in 2021. An alert counts here when it covered any part of the state, so the counties below add up to more than the state. The archive of dense fog advisories reaches back to 2005.

Dense Fog Advisories by county

Each county as a circle sized by its count in 2021. Tap one for its archive.

Dense Fog Advisories: 141
Busiest month: November55 dense fog advisories
Busiest day: November 5, 20215 dense fog advisories

Over time

By month

The alerts

Every alert, in the order issued. Times are local, Pacific Time. Each opens its own page with the text, the map, the radar and the sounding.

Issued	Product	Office	Counties	Lasted
Jan 1, 7:16 AM PST	Dense Fog Advisory	HNX		3 hr
Jan 3, 4:47 AM PST	Dense Fog Advisory	LOX	Los Angeles	4 hr
Jan 5, 3:26 AM PST	Dense Fog Advisory	HNX		8 hr
Jan 5, 3:36 AM PST	Dense Fog Advisory	STO		8 hr
Jan 5, 4:02 AM PST	Dense Fog Advisory	MTR	Alameda, Contra Costa, Marin, Monterey, Napa, San Benito and 5 more	7 hr
Jan 5, 12:06 PM PST	Dense Fog Advisory	HNX		23 hr
Jan 6, 10:19 PM PST	Dense Fog Advisory	STO		13 hr
Jan 7, 2:15 AM PST	Dense Fog Advisory	HNX		9 hr
Jan 7, 8:51 PM PST	Dense Fog Advisory	HNX		14 hr
Jan 8, 12:51 PM PST	Dense Fog Advisory	HNX		20 hr
Jan 8, 1:40 PM PST	Dense Fog Advisory	STO		19 hr
Jan 9, 1:55 PM PST	Dense Fog Advisory	HNX		21 hr
Jan 10, 2:58 AM PST	Dense Fog Advisory	STO		8 hr
Jan 10, 12:57 PM PST	Dense Fog Advisory	HNX		22 hr
Jan 10, 1:04 PM PST	Dense Fog Advisory	STO		22 hr
Jan 11, 12:30 PM PST	Dense Fog Advisory	HNX		18 hr
Jan 12, 1:32 AM PST	Dense Fog Advisory	LOX		4 hr
Jan 14, 4:34 AM PST	Dense Fog Advisory	MTR	Marin, Napa, Sonoma	5 hr
Jan 14, 5:20 AM PST	Dense Fog Advisory	STO		6 hr
Jan 14, 12:26 PM PST	Dense Fog Advisory	HNX		23 hr
Jan 14, 10:22 PM PST	Dense Fog Advisory	STO		13 hr
Jan 15, 12:56 PM PST	Dense Fog Advisory	HNX		22 hr
Jan 16, 12:45 PM PST	Dense Fog Advisory	HNX		20 hr
Jan 16, 7:19 PM PST	Dense Fog Advisory	MFR	Modoc, Siskiyou	16 hr
Jan 17, 11:30 PM PST	Dense Fog Advisory	MFR	Siskiyou	10 hr
Jan 22, 6:49 AM PST	Dense Fog Advisory	PSR	Imperial, Riverside	4 hr
Jan 29, 6:55 PM PST	Dense Fog Advisory	HNX		11 hr
Feb 3, 4:35 AM PST	Dense Fog Advisory	LOX		4 hr
Feb 3, 5:37 AM PST	Dense Fog Advisory	HNX		8 hr
Feb 5, 2:32 AM PST	Dense Fog Advisory	HNX		6 hr
Feb 6, 9:34 PM PST	Dense Fog Advisory	SGX	Orange, San Diego	11 hr
Feb 7, 2:21 AM PST	Dense Fog Advisory	LOX		7 hr
Feb 7, 6:00 AM PST	Dense Fog Advisory	HNX		3 hr
Feb 7, 8:44 PM PST	Dense Fog Advisory	SGX	Orange, San Diego	13 hr
Feb 7, 10:14 PM PST	Dense Fog Advisory	LOX	Los Angeles	11 hr
Feb 8, 12:57 AM PST	Dense Fog Advisory	HNX		8 hr
Feb 15, 9:05 AM PST	Dense Fog Advisory	HNX		8 hr
Feb 16, 9:33 AM PST	Dense Fog Advisory	HNX		4 hr
Mar 12, 2:30 AM PST	Dense Fog Advisory	VEF		4 hr
Apr 4, 4:00 AM PDT	Dense Fog Advisory	SGX	San Diego	4 hr
Apr 4, 8:33 AM PDT	Dense Fog Advisory	SGX	San Diego	2 hr
Apr 17, 11:24 PM PDT	Dense Fog Advisory	EKA	Del Norte, Humboldt	9 hr
Apr 19, 2:17 AM PDT	Dense Fog Advisory	LOX		7 hr
Aug 28, 12:05 AM PDT	Dense Fog Advisory	LOX		9 hr
Sep 5, 4:26 AM PDT	Dense Fog Advisory	LOX		5 hr
Sep 5, 6:34 AM PDT	Dense Fog Advisory	MTR	Marin, Monterey, Napa, City and County of San Francisco, San Mateo, Santa Cruz and 1 more	3 hr
Sep 8, 3:20 AM PDT	Dense Fog Advisory	LOX		5 hr
Sep 22, 5:09 AM PDT	Dense Fog Advisory	LOX		4 hr
Oct 1, 8:55 PM PDT	Dense Fog Advisory	LOX		12 hr
Oct 3, 5:46 AM PDT	Dense Fog Advisory	EKA	Del Norte, Humboldt	4 hr
Oct 4, 2:13 AM PDT	Dense Fog Advisory	EKA	Del Norte, Humboldt	8 hr
Oct 25, 5:22 AM PDT	Dense Fog Advisory	PSR	Imperial	3 hr
Oct 26, 6:50 AM PDT	Dense Fog Advisory	HNX	Fresno, Kings, Tulare	5 hr
Oct 26, 1:52 PM PDT	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Mariposa, Merced and 1 more	18 hr
Oct 29, 3:59 AM PDT	Dense Fog Advisory	STO		7 hr
Oct 29, 7:09 PM PDT	Dense Fog Advisory	LOX		14 hr
Oct 29, 9:29 PM PDT	Dense Fog Advisory	SGX	Orange, San Diego	12 hr
Oct 30, 5:04 AM PDT	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Mariposa, Merced and 1 more	7 hr
Oct 31, 5:03 AM PDT	Dense Fog Advisory	PSR	Imperial	4 hr
Oct 31, 8:55 PM PDT	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Mariposa, Merced and 1 more	9 hr
Nov 3, 4:35 AM PDT	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Merced, Tulare	7 hr
Nov 3, 5:41 AM PDT	Dense Fog Advisory	LOX	Los Angeles	4 hr
Nov 3, 5:42 AM PDT	Dense Fog Advisory	MTR	Monterey, San Benito	3 hr
Nov 3, 10:46 PM PDT	Dense Fog Advisory	LOX	Los Angeles	10 hr
Nov 4, 11:05 PM PDT	Dense Fog Advisory	LOX		10 hr
Nov 5, 1:03 AM PDT	Dense Fog Advisory	SGX	Orange, San Diego	14 min
Nov 5, 1:17 AM PDT	Dense Fog Advisory	SGX	Orange, San Diego	8 hr
Nov 5, 1:23 PM PDT	Dense Fog Advisory	LOX		16 hr
Nov 5, 1:35 PM PDT	Dense Fog Advisory	SGX	Orange, Riverside, San Bernardino, San Diego	11 hr
Nov 7, 1:23 AM PST	Dense Fog Advisory	LOX	Los Angeles	8 hr
Nov 7, 2:45 AM PST	Dense Fog Advisory	SGX	Riverside, San Bernardino, San Diego	6 hr
Nov 7, 6:42 AM PST	Dense Fog Advisory	PSR	Imperial	3 hr
Nov 8, 2:34 AM PST	Dense Fog Advisory	PSR	Imperial	5 hr
Nov 9, 7:35 AM PST	Dense Fog Advisory	PSR	Imperial	85 min
Nov 10, 12:24 AM PST	Dense Fog Advisory	LOX		6 hr
Nov 10, 3:45 AM PST	Dense Fog Advisory	STO		6 hr
Nov 10, 4:16 AM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Merced, Tulare	7 hr
Nov 10, 9:30 PM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Merced, Tulare	13 hr
Nov 11, 1:12 PM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Mariposa, Merced and 1 more	21 hr
Nov 12, 1:30 AM PST	Dense Fog Advisory	STO		9 hr
Nov 12, 2:59 AM PST	Dense Fog Advisory	MFR	Modoc, Siskiyou	7 hr
Nov 12, 7:37 AM PST	Dense Fog Advisory	MTR	Alameda, Contra Costa, Marin, Napa, San Mateo, Santa Clara and 1 more	2 hr
Nov 12, 1:08 PM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Mariposa, Merced and 1 more	23 hr
Nov 12, 6:44 PM PST	Dense Fog Advisory	STO		17 hr
Nov 12, 11:02 PM PST	Dense Fog Advisory	MTR	Alameda, Contra Costa, Marin, Napa, City and County of San Francisco, San Mateo and 2 more	13 hr
Nov 13, 12:50 PM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Mariposa, Merced and 1 more	24 hr
Nov 13, 8:28 PM PST	Dense Fog Advisory	STO		15 hr
Nov 13, 9:35 PM PST	Dense Fog Advisory	MTR	Alameda, Contra Costa, Marin, Napa, City and County of San Francisco, San Mateo and 2 more	13 hr
Nov 14, 2:20 AM PST	Dense Fog Advisory	EKA	Humboldt	10 hr
Nov 14, 1:37 PM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Mariposa, Merced and 1 more	22 hr
Nov 14, 11:38 PM PST	Dense Fog Advisory	STO		11 hr
Nov 15, 12:30 PM PST	Dense Fog Advisory	LOX	Los Angeles	22 hr
Nov 15, 2:50 PM PST	Dense Fog Advisory	SGX	Orange, San Diego	19 hr
Nov 15, 8:07 PM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Mariposa, Merced and 1 more	12 hr
Nov 15, 11:53 PM PST	Dense Fog Advisory	MTR	Alameda, Contra Costa, Marin, Monterey, Napa, San Benito and 2 more	11 hr
Nov 18, 4:19 AM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Mariposa, Merced and 1 more	6 hr
Nov 19, 1:40 AM PST	Dense Fog Advisory	LOX	Los Angeles	7 hr
Nov 19, 3:27 AM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Mariposa, Merced and 1 more	8 hr
Nov 19, 4:00 AM PST	Dense Fog Advisory	SGX	Riverside, San Bernardino, San Diego	5 hr
Nov 19, 4:50 PM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Mariposa, Merced and 1 more	18 hr
Nov 20, 2:50 AM PST	Dense Fog Advisory	LOX	Los Angeles	6 hr
Nov 20, 3:00 AM PST	Dense Fog Advisory	SGX	Riverside, San Bernardino, San Diego	6 hr
Nov 21, 2:23 AM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Mariposa, Merced and 1 more	9 hr
Nov 21, 10:53 AM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Tulare	2 hr
Nov 21, 10:30 PM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Mariposa, Merced and 1 more	12 hr
Nov 21, 11:22 PM PST	Dense Fog Advisory	STO		11 hr
Nov 22, 10:06 AM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Mariposa, Merced and 1 more	112 min
Nov 22, 4:54 PM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Mariposa, Merced and 1 more	19 hr
Nov 23, 4:50 AM PST	Dense Fog Advisory	STO		5 hr
Nov 24, 2:24 AM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Mariposa, Merced and 1 more	8 hr
Nov 24, 1:25 PM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Mariposa, Merced and 1 more	22 hr
Nov 28, 8:13 AM PST	Dense Fog Advisory	EKA	Del Norte, Humboldt	4 hr
Nov 29, 11:40 PM PST	Dense Fog Advisory	LOX		9 hr
Nov 30, 12:45 AM PST	Dense Fog Advisory	SGX	Orange, San Diego	8 hr
Nov 30, 5:20 PM PST	Dense Fog Advisory	LOX		17 hr
Dec 1, 2:05 AM PST	Dense Fog Advisory	STO		8 hr
Dec 1, 5:15 AM PST	Dense Fog Advisory	SGX	Orange, San Diego	4 hr
Dec 1, 1:37 PM PST	Dense Fog Advisory	SGX	Orange, San Diego	20 hr
Dec 1, 1:54 PM PST	Dense Fog Advisory	LOX	Los Angeles	20 hr
Dec 2, 2:05 AM PST	Dense Fog Advisory	STO		8 hr
Dec 2, 11:27 PM PST	Dense Fog Advisory	STO		11 hr
Dec 3, 2:20 AM PST	Dense Fog Advisory	HNX	Fresno, Madera, Merced, Tulare	9 hr
Dec 3, 5:34 PM PST	Dense Fog Advisory	SGX	Orange, Riverside, San Bernardino, San Diego	15 hr
Dec 3, 7:04 PM PST	Dense Fog Advisory	STO		17 hr
Dec 3, 10:39 PM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Mariposa, Merced and 1 more	12 hr
Dec 4, 6:31 PM PST	Dense Fog Advisory	SGX	Riverside, San Bernardino, San Diego	14 hr
Dec 4, 11:10 PM PST	Dense Fog Advisory	STO		11 hr
Dec 5, 1:12 AM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Tulare	8 hr
Dec 5, 2:59 AM PST	Dense Fog Advisory	LOX	Los Angeles	6 hr
Dec 5, 7:06 AM PST	Dense Fog Advisory	MTR	Marin, Monterey, Napa, San Benito, Sonoma	3 hr
Dec 6, 12:18 AM PST	Dense Fog Advisory	MTR	Alameda, Contra Costa, Marin, Monterey, Napa, San Benito and 1 more	10 hr
Dec 7, 10:12 PM PST	Dense Fog Advisory	MFR	Siskiyou	10 hr
Dec 8, 4:42 AM PST	Dense Fog Advisory	LOX		4 hr
Dec 8, 5:10 AM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Mariposa, Merced and 1 more	5 hr
Dec 18, 7:18 AM PST	Dense Fog Advisory	STO		4 hr
Dec 19, 6:42 AM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Merced, Tulare	5 hr
Dec 19, 8:10 PM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Mariposa, Merced and 1 more	16 hr
Dec 20, 2:41 AM PST	Dense Fog Advisory	LOX		6 hr
Dec 21, 11:22 PM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Tulare	8 hr
Dec 30, 8:43 PM PST	Dense Fog Advisory	HNX	Fresno, Kern, Kings, Madera, Merced, Tulare	10 hr
Dec 31, 7:19 AM PST	Dense Fog Advisory	HNX	Kern	8 hr

By county

Every county with at least one alert. A county page lists each alert that covered it.

The busiest days

Days with the most alerts issued, by UTC date.

Nearby

Alerts in force now Tornadoes on record The radar archive 2020 2022

Sources

National Weather Service watches, warnings, advisories and statements from the Iowa Environmental Mesonet's VTEC archive, which reconstructs tornado, severe thunderstorm, flash flood and marine warnings back to 1986 from the NWS text archive. Storm Prediction Center watches and mesoscale discussions from SPC's archive through the Mesonet. County centers from the US Census Bureau. Warning verification from the Mesonet's Cow. Rebuilt daily.