Farragut North is one of the stations with no chiller.

Jordan Pascale / WAMU

The Washington region is in the middle of a dangerous heat wave, as heat indices rise past 110 degrees. The situation can be even worse in some underground Metro stations.

The chilling units at the Dupont Circle and Farragut North stations have been broken for years and the unit at Union Station has had problems recently. Metro says the three stations’ chillers should be fixed by the end of the month. They’ve been using giant fans to try to keep things cooler in the meantime.

The chillers, when they work, lower the temperature about 10 degrees from the outdoor air temp. It’s not technically air conditioning, rather the units pump chilled water throughout stations that helps bring temperatures down.

To see just how these stations get, we took a handheld thermometer around parts of the system Thursday afternoon, when temperatures outside reached 88 to 94 degrees.

Here’s what our little thermometer said around the system.

Georgia Ave./Petworth — 75.2 degrees

The first station on our trip was the coolest and it only got progressively worse throughout…

7000-series Metrorail car — 81.5 degrees

This 7000-series train is a bit warmer than it should be, according to Roger Bowles of Rail Transit Ops, an independent group that monitors Metro.

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Fort Totten — 90.5 degrees

The temp at our first outdoor station hovered around 90.5 degrees, but it felt a lot cooler under the station canopy.

Forest Glen — 90.6 degrees outside and 91.7 degrees underground

At 196 feet in the ground, Forest Glen is the deepest station in the system, so one might assume it would escape the heat. Not so. It was 90.6 degrees above ground (only accessible by speedy elevators) and 91.7 degrees underground.

Brookland — 92.1 degrees

Brookland is another outdoor station, and it’s smack dab in the middle of a “heat island.” That’s when an area surrounded by pavement and asphalt absorb heat and radiates it out. There are lots of buildings but not a ton of green space to help cool the area.

National Geographic reports, “On a hot day in Washington, D.C., temperatures varied nearly 17 degrees between the warmest spot and the coolest.”

Union Station (no chiller) — 94.4 degrees

Union Station was the first we went to without a chiller and it was also the hottest station we went to all day. Fans are set up and that helps if you’re right in front of them, but several people were jockeying for those spaces.

Here’s a great explainer about why humans thrive at around 70 degrees.

Metro Center — 88.3 degrees

Even if chillers are working, like they were here, it still can be hot.

Farragut North (no chiller) — 93 degrees

Another station with no chiller. And what’s holding up the year-long fix? A surprise light pole.

Dupont Circle (no chiller) — 94.8 outside, 93.9 degrees inside

Our last stop also had no chiller. At the end of our trip, temperatures hit nearly 94.8 degrees outside Dupont Circle and 93.9 underground.

Your best bet to beat the heat is to stay hydrated, keep a cool towel around your neck and stay in front of those Metro fans. Unlike prior heat waves, Metro has so far not given riders permission to drink water within the system. It’s against the rules to eat or drink on Metro. It’s a civil penalty some places and criminal offense in others.

Keep an eye on train arrival times with apps like MetroHero or Transit and time your walk to the station so you don’t wait there too long — especially on weekends with infrequent service.

Or just stay inside if you don’t have to travel.

This story originally appeared on WAMU.