Weather & Tides-August 21, 2025

NATIONAL WEATHER SERVICE REPORT 

Thursday, August 21st, 2025

SYNOPSIS: Hot and very dry weather will build in through the week with a shallower and stronger marine layer along the coast. There is very slight potential for thunderstorms over the interior this weekend into early next week.

TODAY: 

Inland: Sunny, with a high near 98. North wind 5 to 11 mph.

Along the Coast: Mostly sunny, with a high near 66. Light and variable wind becoming northwest 5 to 10 mph in the afternoon. 

TONIGHT:  

Inland: Mostly clear, with a low around 54. North wind 6 to 11 mph becoming light north northwest in the evening. 

Along the Coast: Increasing clouds, with a low around 54. Northwest wind 5 to 8 mph becoming calm in the evening. 

Extended Forecast: A strong high-pressure system is settling in and will drive temperatures well above 100°F in many inland valleys today, peaking around 105–110°F Friday and Saturday. The heat, paired with warm nights in the mid-60s, will bring moderate to locally major heat risks, especially in valleys like Trinity and Russian River. Along the coast, low clouds will stick around, but some weaker winds may let warmer air slip in with a small chance of coastal highs near 70°F this weekend. Early next week, temperatures ease slightly as the high weakens, but added humidity keeps the heat risk about the same, and there’s a small chance (10–20%) of isolated, mostly dry thunderstorms over the mountains.

Predicted Temperatures

Location	High Today	Low Tonight	HighTomorrow
Inland	98	54	102
Along The Coast	66	54	66

The coastal waters forecast from Point Saint George to Cape Mendocino and out to 10 nautical miles.

SMALL CRAFT ADVISORY IN EFFECT FROM THIS AFTERNOON THROUGH LATE TONIGHT

Today	Wind	NW 5 to 10 kt.
	Waves	NW 5 ft at 7 seconds. Patchy dense fog this morning.
Tonight	Wind	SW 5 to 10 kt.
	Waves	NW 6 ft at 7 seconds.

The coastal waters forecast from Cape Mendocino to Point Arena and out to 10 nautical miles. 

SMALL CRAFT ADVISORY IN EFFECT THROUGH LATE TONIGHT

Today	Wind	NW 20 to 25 kt.
	Waves	NW 6 ft at 7 seconds and SW 2 ft at 15 seconds.
Tonight	Wind	NW 20 to 25 kt with gusts up to 35 kt.
	Waves	N 7 ft at 7 seconds and SW 2 ft at 15 seconds.

Lastly, here are the solar and lunar phases and tidal information : Today, Thursday, August 21st, the sun rose in Shelter Cove at 6:34am and the sunset will be at 8:03pm, for a total of 13 hours and 28 minutes of sunlight. The first high tide will be at 11:38 am, at 5ft.,  and the next high tide at 10:30 pm, at 6.8ft. The next low tide will be at 4:33 pm,  at 2.7ft. The waning crescent moon rose in the northeast at 4:38 am and will set in the northwest at 7:35 pm.  According to the solunar theory, today is a good day for fishing, the fish activity forecast is high.