The summer of 2018 has been noteworthy for the all-time heat records smashed around the world, from California to Sweden and Japan.

Why it matters: The heat is a sign of a warming world, scientists have said, with human-caused global warming raising the odds of heat waves as well as increasing their severity and duration.

This visualization (above) shows the high temperature records set from May 1 through July 31, as compiled by Berkeley Earth, a nonprofit group that monitors global temperatures. Axios plotted daily record highs, monthly record highs and all-time record highs.

We did not include record lows because only daily record lows were made available. However, according to the National Centers for Environmental Information, warm temperature records have been significantly outpacing cold ones, including monthly and all-time cold records, worldwide so far this year. This was especially the case this summer.

By the numbers

Some of the records represented by the dots on the map include:

Norway set a new national maximum temperature record when temperatures soared to 33.5°C, or 92.3°F, on July 17 in Bardufoss. Norway also set a new warm national minimum temperature when it dropped to only 25.2°C, or 77.4°F, on July 18.

when temperatures soared to 33.5°C, or 92.3°F, on July 17 in Bardufoss. Norway also set a new warm national minimum temperature when it dropped to only 25.2°C, or 77.4°F, on July 18. Warmer-than-average temperatures engulfed much of Sweden during July 2018, with several locations setting new monthly temperature records.

during July 2018, with several locations setting new monthly temperature records. Montreal, Canada also set its all-time high temperature record , during a deadly Quebec heat wave in early July.

, during a deadly Quebec heat wave in early July. California set its record for the warmest July on record , while Death Valley set a record for the hottest month ever recorded on Earth.

, while Death Valley set a record for the hottest month ever recorded on Earth. Japan set a national temperature record of 106°F, or 41.1°C, in a heat wave that followed deadly floods.

of 106°F, or 41.1°C, in a heat wave that followed deadly floods. In the Middle East: Quriyat, Oman, likely set the world’s hottest low temperature ever recorded on June 28, when the it failed to drop below 109°F, or 42.8°C.

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