How warm is it in Key West in May?

Daytime highs averaged 27.7 °C, night-time lows 26.8 °C. The highest value of the past 10 years was 30.3 °C (30 May 2024), the lowest 23.5 °C (7 May 2017).

How often does it rain in Key West in May?

On average there were 16.4 rain days (at least 1 mm) with 122 mm of precipitation in total.

How warm is the sea in Key West in May?

The sea temperature averaged 28.0 °C (open-sea point approx. 3 km from the town).

Holiday Weather Rewind

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Key West weather in May: temperature & rain

Photo: Juliancolton · Public domain

🇺🇸 Weather in Key West in May

This is what the weather in Key West (Florida, USA) was like in May over the years 2017–2026.

Key facts at a glance

Prevailing weather: Light rain

Avg. daytime high

27.7 °C

26.5 °C – 28.7 °C

Avg. night-time low

26.8 °C

25.6 °C – 27.8 °C

Avg. rain days in period

16.4

53 % of days · ≥ 1.0 mm

Avg. precipitation in period

122 mm

11.7 mm – 377 mm

Avg. cloud cover

44 %

This data source has no sunshine hours – average cloud cover is shown instead.

Avg. sea temperature

28.0 °C

Sea temperature available for 9 of 10 years.

Extremes: Highest temperature 30.3 °C (30 May 2024) · Lowest temperature 23.5 °C (7 May 2017) · Avg. daily peak wind 23 km/h

Weather mix of all days

80Sunny
52Partly cloudy
14Cloudy
107Light rain
57Rain

Summary

On average 27.7 °C during the day and 26.8 °C at night.
On average 16.4 rain days (Rain day = at least 1.0 mm of precipitation) with 122 mm of precipitation in total.
The sea averaged 28.0 °C.
Prevailing weather: Light rain.
Warmest year: 2024 (avg. 28.7 °C), coolest: 2018 (avg. 26.5 °C).
Wettest year: 2020 (377 mm), driest: 2017 (11.7 mm).
Extremes: 30.3 °C on 30 May 2024 and 23.5 °C on 7 May 2017.

Overall values from all 10 years. How is this calculated?

Temperatures per year

Average over your travel period

Precipitation & rain days

Year by year

2026
Avg. max28.5°Avg. min27.5°
Rain days
27 Rain days
Precipitation
221 mm
Avg. cloud cover
51 % cloudy
Sea temperature
28.3 °C
Max 30.0 °C · Min 24.7 °C
2025
Avg. max28.2°Avg. min27.2°
Rain days
10 Rain days
Precipitation
55.7 mm
Avg. cloud cover
30 % cloudy
Sea temperature
28.1 °C
Max 29.7 °C · Min 25.1 °C
2024
Avg. max28.7°Avg. min27.8°
Rain days
16 Rain days
Precipitation
157 mm
Avg. cloud cover
21 % cloudy
Sea temperature
29.1 °C
Max 30.3 °C · Min 25.5 °C
2023
Avg. max27.9°Avg. min26.7°
Rain days
20 Rain days
Precipitation
72.2 mm
Avg. cloud cover
39 % cloudy
Sea temperature
28.7 °C
Max 29.0 °C · Min 24.0 °C
2022
Avg. max27.6°Avg. min26.7°
Rain days
24 Rain days
Precipitation
183 mm
Avg. cloud cover
44 % cloudy
Sea temperature
28.2 °C
Max 28.7 °C · Min 24.8 °C
2021
Avg. max27.9°Avg. min27.0°
Rain days
9 Rain days
Precipitation
42.1 mm
Avg. cloud cover
46 % cloudy
Sea temperature
27.5 °C
Max 29.1 °C · Min 25.8 °C
2020
Avg. max27.3°Avg. min26.2°
Rain days
22 Rain days
Precipitation
377 mm
Avg. cloud cover
61 % cloudy
Sea temperature
27.2 °C
Max 28.9 °C · Min 24.2 °C
2019
Avg. max27.8°Avg. min27.0°
Rain days
11 Rain days
Precipitation
28.1 mm
Avg. cloud cover
36 % cloudy
Sea temperature
28.1 °C
Max 28.4 °C · Min 25.7 °C
2018
Avg. max26.5°Avg. min25.6°
Rain days
20 Rain days
Precipitation
71.5 mm
Avg. cloud cover
81 % cloudy
Sea temperature
26.7 °C
Max 27.4 °C · Min 24.5 °C
2017
Avg. max27.1°Avg. min26.2°
Rain days
5 Rain days
Precipitation
11.7 mm
Avg. cloud cover
36 % cloudy
Sea temperature
–
Max 28.7 °C · Min 23.5 °C

Frequently asked questions

How warm is it in Key West in May?: Daytime highs averaged 27.7 °C, night-time lows 26.8 °C. The highest value of the past 10 years was 30.3 °C (30 May 2024), the lowest 23.5 °C (7 May 2017).
How often does it rain in Key West in May?: On average there were 16.4 rain days (at least 1 mm) with 122 mm of precipitation in total.
How warm is the sea in Key West in May?: The sea temperature averaged 28.0 °C (open-sea point approx. 3 km from the town).

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Data sources

Weather data: Data obtained from the NASA Langley Research Center (LaRC) POWER Project funded through the NASA Earth Science/Applied Science Program
Reanalysis (weather model constrained by observations) on a coarse grid of about 50 km. Values represent a large area and can differ from local conditions, especially on islands, coasts and in mountains. Snow depth is the model value for the grid cell, not the depth on the slopes. No sunshine duration.
Reanalysis (weather model constrained by observations)
Reanalysis values represent a grid cell (approx. 25–50 km) and may differ from local measurements on coasts, islands and in mountains.
Sea temperature: MUR SST data were provided by JPL under support by NASA MEaSUREs program; accessed via NOAA CoastWatch ERDDAP
Daily multi-scale ultra-high resolution (≈ 1 km) analysis of satellite measurements (infrared, microwave) and in-situ data. Represents the foundation temperature below the daily warm surface layer. (Satellite and in-situ analysis); Sea measuring point approx. 3 km from the location (24.590, -81.780)
Place search: Natural Earth (public domain) · GeoNames (CC BY 4.0) / OpenStreetMap (ODbL)