So we’ve entered that crucial “September to November period when fire risk is greatest,” according to the UCSF letter.

Mount Sutro is squarely in the fog belt. The question is, Whether between the end of summer (and fog) and the beginning of winter (and rain), is there enough dryness to raise fire risk? We’ll find out. What we’re starting here is a Fog Log. It will be updated for every day’s weather. We will also look out for the “dry hot winds” blowing “from the Northeast.”

September summary: 7 fogless days. Maximum consecutive fogless days: 2

[Edited to Add: At the end, we posted the Fog Log Conclusion: Seven Dry Days

“Here are the results: In the three months, the longest stretch the forest was without either fog or rain was ONLY 7 DAYS.”]

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September 1st Week: 6 days; of which 2 consecutively fogless – defined as days with no fog morning or evening.

It’s very foggy now as we write (Sept 5th). It came in earlier in the day and became denser toward evening. So far, we have had two hot fogless days: Sept 2 & 3 with wind from the north-west or the west. By Sept 3 evening, the fog blew in on the wind from the sea. The winds have been westerly. Sept 6th: Woke to fog. Around noon the sun broke through.

September 2nd Week: Of 7 days, 2 fogless, but no consecutive fogless days.

Sept 7: Bright and sunny, (high 60s/ low70s max), westerly wind. Sept 8: Started out sunny. At 4.30 p.m, the fog arrived. Sept 9: Some bright blue sky, and then fog mixed in. Sept 10: Sunny and clear. Sept 11: Started out clear. Fog came in around 7.30 p.m. Wind is westerly, 20mph. Sept 12: Weird weather; very loud thunder early in the morning, splats of rain, dense fog not burning off. Sept 13: Some rain.

September 3rd Week: Fogless days, 1; fogless streak, 0.

Sept 14: Morning and evening fog. Sept 15th: Sunny in the day, thick fog at night. Sept 16: Dense morning fog. Sept 17: Morning fog, burning off around 10.30 a.m. Sept 18: Bright and clear.      Sept 19: Foggy nearly all day. Sept 20: Foggy morning, burned off around 10.30 a.m. – and came back around 5. I can’t even see the forest. (It cleared later – around 8.30 p.m.)

September 4th Week: Fogless days, 2; fogless streak, 2

This is a week to watch out. The weather forecast is for hot weather at the start of the week. (ETA: Nope.)

Sept 21: Morning and evening fog. Cool and sunny in between. Who stole our heatwave? Sept 22: Overnight fog. Bright and sunny later, foggy again by 7.30 p.m. Sept 23: Morning fog. Afternoon fog. Evening fog. Sept 24: Foggy all day. Walked in the forest; it was raining in there. Not in the Dry Garden, though. (See the pictures.) Sept 25: Morning fog, burning off to bright sunshine. Sept 26: Sunny! Sept 27: Sunny. Again! (Late night fog).

September 5th Week: Fogless days, 2; fogless streak, 2

Sept 28: Clouds, some fog. Sept 29: Sunny with clouds. Sept 30: Sunny!