Currently in San Francisco — July 12, 2023: Sunny, windy day.

The weather, currently.

As the heat comes through, we can expect humidity to drop substantially (60% on Tuesday to below 30% on Friday). With the wild winter we had, fire fuels are abundant and we will have elevated fire risk in low-lying grasslands and the foothills of mounts. If any fires do spark, the low humidity increases their chances of spreading. So, as you enjoy this summer weather and maybe take some reprieve in the shade, keep an eye out for smoke and warning from Cal Fire. Watch Duty is also a great resource for tracking wildfires.

—Priya Shukla

What you can do, currently.

The climate emergency doesn’t take the summer off. In fact — as we’ve been reporting — we’re heading into an El Niño that could challenge historical records and is already supercharging weather and climate impacts around the world.

When people understand the weather they are experiencing is caused by climate change it creates a more compelling call to action to do something about it.

If these emails mean something important to you — and more importantly, if the idea of being part of a community that’s building a weather service for the climate emergency means something important to you — please chip in just $5 a month to continue making this service possible.

Thank you!!

What you need to know, currently.

Southern California will be the epicenter of one of the most intense heat waves ever recorded in the US Southwest this week.

Temperatures in Death Valley are expected to reach 130°F (54.4°C), challenging an all-time world record. The duration and intensity of this particular heat wave is also giving authorities caution, with the National Weather Service’s excessive heat outlook reaching ‘extreme’ for areas just inland of Los Angeles.

The heat wave comes courtesy of an especially strong high pressure system, which will act to dry out the atmosphere and cause additional heating due to descending air across the region. The name for this phenomenon is a heat dome, which can be self-reinforcing if it persists over the same region for a long enough period of time.

The California Department of Public Health has helpful information on how to stay cool — and safe — in this deadly heat.

—Eric Holthaus