ERA-5 Daily Climatology Fields
This page explains each field shown in the ERA-5 Daily Climatology experience.
Data source
Where does the data come from?
We use post-processed ERA5 climate data from ECMWF for the exact coordinates you select (1982-2024). It is long-term climatology, not a short-term forecast.
Temperature
Avg Temperature
Mean daily temperature across your date range, averaged over many years. Values are smoothed with a 31-day running average to reduce noise.
Min / Max
Average daily minimum and maximum temperatures for the same dates, based on the long-term daily climatology.
Day-to-day swing
An average of how much temperatures tend to vary for those calendar days across past years. Higher values mean less consistency year to year.
Rain & precipitation
Daily Rain Chance
Average daily probability of measurable precipitation during your selected dates (climatological probability).
Avg Precipitation
Average total precipitation per day across your date range. Source data is in mm/day and converted to your preferred units.
Variability +/-
One standard deviation of daily precipitation totals across years for each day of year. It signals how much daily rain amounts typically vary.
Rainfall season label
Relative to typical daily totals:
| Label | Value |
|---|---|
| Very low | <1 mm/day |
| Low | 1-2.5 mm/day |
| Moderate | 2.5-5 mm/day |
| High | 5-10 mm/day |
| Very high | >=10 mm/day |
Sunshine & wind
Sunny Day Chance
Probability that the sunshine fraction exceeds 70% for the day. A sunny day means mostly clear skies throughout.
Wind Speed
Average near-surface wind speed (10m height) for your dates. Min/max show the typical range of daily mean winds.
Comfort indicators (Pro)
Beach Day Chance
Probability of ideal beach conditions: hot (max temp >=26C), sunny (>=65% sunshine), dry (<1mm rain), and calm winds (<10 m/s).
| Threshold | Value |
|---|---|
| Max temp | >=26C (79F) |
| Sunshine | >=65% |
| Rain | <1 mm/day |
| Wind | <10 m/s |
Muggy Day Chance
Probability of uncomfortably humid conditions: warm (mean temp >=20C) with high humidity (dewpoint >=18C) and not too windy.
| Threshold | Value |
|---|---|
| Mean temp | >=20C (68F) |
| Dewpoint | >=18C (64F) |
| Wind | <12 m/s |
Pleasant Day Chance
Probability of comfortable outdoor conditions: mild temps (18-26C), low humidity (dewpoint <16C), dry (<1mm rain), and calm.
| Threshold | Value |
|---|---|
| Mean temp | 18-26C (64-79F) |
| Dewpoint | <16C (61F) |
| Rain | <1 mm/day |
| Wind | <10 m/s |
Humidity
Average relative humidity for your dates. Higher values feel more oppressive, especially when warm.
Cloud Cover
Average fraction of sky covered by clouds (0-100%). Lower values mean clearer, sunnier skies.
Winter indicators (Pro)
Snowy Day Chance
Probability of snow presence: either snow on the ground (>=2cm depth) or fresh snowfall (>=1mm water equivalent).
Snowfall Day Chance
Probability of active snowfall: at least 1mm snowfall (water equivalent) with max temperature at or below 2C.
Snow Cover Chance
Probability of significant snow on the ground (>=5cm depth). Useful for skiing or winter activities.
Severe weather (Pro)
Stormy Day Chance
Probability of impactful weather: strong winds (mean >=11 m/s or gusts >=16 m/s), heavy rain (>=10mm), or very cloudy (>=85% cover).
| Threshold | Value |
|---|---|
| Mean wind | >=11 m/s |
| Wind gusts | >=16 m/s |
| Rain | >=10 mm/day |
| Cloud cover | >=85% |
Annual patterns
Annual patterns charts
Daily means across the full year with a variability band (+/- one standard deviation). The highlighted band matches your trip dates.
How to interpret
What this means
These numbers describe typical conditions and variability, not exact weather. Actual conditions can differ year to year.