Heat may pose a threat to athletes and spectators alike at some of the venues for the Tokyo 2020 Olympics, government officials say.

According to temperature readings taken last summer at three of the venues, all showed heat gauge indications on certain days saying sports “should be avoided.”

According to Meteorological Agency data from the main observation point in the capital, there were only five days last August in which the high was below 30 degrees. On one day it hit 37.7.

The Cabinet Secretariat, which is in charge of preparations for the games, took wet bulb globe temperature readings, a measure of heat stress, from late July to mid-August at three venues: Kasumigaseki Country Club, the golf venue in Saitama Prefecture, the Enoshima sailing area in Kanagawa and Tokyo’s Ariake area.

They logged at least four days of WBGT readings indicating a high risk of heatstroke or heat exhaustion at areas with direct sunlight at all three venues.

The government has decided to take more detailed measurements and plans to earmark a budget for a new survey when fiscal 2017 begins in April, the officials said.

The 2020 Tokyo Olympics will run from July 24 to Aug. 9, and the Paralympics from Aug. 25 to Sept. 6 — the hottest and most humid part of the year in the Tokyo metropolitan area.

Since many athletes unfamiliar with Tokyo’s hot and muggy climate will be competing, the government plans to take road-paving and other measures to keep temperatures from rising too high.