Weather statistics, phenology and records
Monthly averages, climate normals, phenology, growing degree days and weather records for Mustamäe, Tallinn, Estonia.
Highest temperature
27.9 C
18 Jul
Lowest temperature
-17.0 C
25 Jan
Total precipitation
229.8 mm
65 Rain days
Strongest wind gust
46.1 mph
25 Apr
Monthly averages
| Month | Avg temp | Max temp | Min temp | Precipitation | Rain days |
|---|---|---|---|---|---|
| Jan | -7.5 C | -1.5 C | -17.0 C | 0.0 mm | 0 |
| Feb | -6.9 C | 3.6 C | -16.2 C | 3.8 mm | 3 |
| Mar | 4.4 C | 15.7 C | -1.5 C | 6.2 mm | 9 |
| Apr | 5.6 C | 15.4 C | -1.2 C | 13.8 mm | 5 |
| May | 11.9 C | 24.2 C | 2.1 C | 33.8 mm | 9 |
| Jun | 16.9 C | 26.3 C | 9.1 C | 74.0 mm | 13 |
| Jul | 18.1 C | 27.9 C | 8.6 C | 81.4 mm | 19 |
| Aug | 17.5 C | 25.1 C | 12.5 C | 16.8 mm | 7 |
| Sep | -- | -- | -- | -- | -- |
| Oct | -- | -- | -- | -- | -- |
| Nov | -- | -- | -- | -- | -- |
| Dec | -- | -- | -- | -- | -- |
Season Tracker 2026
🌸 Spring days
101
Days with T_max ≥ 15°C
☀️ Summer days
15
Days with T_max ≥ 25°C
🔥 Tropical days
0
Days with T_max ≥ 30°C
❄️ Frost days
73
Days with T_min < 0°C
🧊 Ice days
55
Days with T_max < 0°C
🌧️ Precipitation days
65
Days with rain ≥ 0.1 mm
Seasonal milestones
| Milestone | 2026 | Difference |
|---|---|---|
| 🌸 First spring day | 14 Mar | 32 days earlier |
| ☀️ First summer day | 04 Jun | 12 days later |
| 🌡️ First tropical day | — | — |
| ❄️ Last spring frost | 11 Apr | 8 days earlier |
| 🍂 First autumn frost | — | — |
| 🧊 First ice day | 01 Jan | 36 days earlier |
Growing Degree Days (base 10 °C) — Total GDD: 684
Peak GDD period
Shows daily GDD bars and a 14-day rolling total so warm stretches stand out.
Best 14-day period
19 Jun
– 2 Jul
130.2 GDD
Average per day: 9.3 GDD
What are Growing Degree Days?
Growing Degree Days (GDD) measure accumulated heat above a base temperature — not calendar days.
GDD = max(0, (Tmax + Tmin) / 2 − 10)
Each day contributes a value equal to how many degrees the average temperature exceeds 10 °C. A day with a high of 26 °C and a low of 12 °C contributes (26 + 12) / 2 − 10 = 9 GDD.
The total GDD for a year is the sum of all daily values. A warm summer can easily produce 1 000 – 1 500 GDD, which is why the total is much larger than 365.
Base temperature: 10 °C (growing threshold for most plants in temperate climates).
All-time records
Highest temperature
32.9 C
29 Jul 2018
#2
32.2 C
21 Jun 2021
#3
32.1 C
22 Jun 2021
#4
32.1 C
10 Jul 2021
#5
31.8 C
28 Jun 2022
Lowest temperature
-19.2 C
04 Jan 2024
#2
-19.1 C
03 Jan 2024
#3
-17.6 C
18 Feb 2021
#4
-17.6 C
07 Dec 2021
#5
-17.4 C
02 Jan 2024
Warmest day (avg)
27.5 C
21 Jun 2021
#2
27.5 C
22 Jun 2021
#3
27.1 C
29 Jul 2018
#4
27.0 C
10 Jul 2021
#5
26.9 C
27 Jun 2022
Coldest day (avg)
-17.8 C
03 Jan 2024
#2
-16.4 C
02 Jan 2024
#3
-16.1 C
04 Jan 2024
#4
-14.8 C
06 Dec 2021
#5
-14.5 C
27 Feb 2018
Largest daily range
17.0 C
25 Aug 2024
#2
16.3 C
14 May 2018
#3
16.0 C
14 Apr 2018
#4
15.2 C
10 May 2021
#5
15.0 C
21 May 2019
Most precipitation (day)
27.6 mm
30 Jun 2020
#2
25.6 mm
11 Jun 2026
#3
23.4 mm
20 Apr 2025
#4
23.0 mm
02 Jul 2023
#5
22.8 mm
14 Sep 2024
Highest rain rate
243.4 mm
16 Dec 2023
#2
169.0 mm
02 Aug 2017
#3
99.2 mm
23 Jun 2021
#4
90.6 mm
02 Aug 2018
#5
86.0 mm
11 Jun 2024
Strongest wind gust
70.0 mph
07 Oct 2023
#2
59.1 mph
18 Dec 2019
#3
57.0 mph
19 Jun 2018
#4
57.0 mph
09 Mar 2019
#5
53.0 mph
27 Mar 2017
Highest average wind
22.6 mph
07 Oct 2023
#2
20.7 mph
17 Sep 2020
#3
20.2 mph
08 Oct 2023
#4
19.9 mph
02 Nov 2024
#5
19.4 mph
14 Jan 2022
Highest pressure
1050 hPa
07 Feb 2025
#2
1050 hPa
08 Feb 2025
#3
1047 hPa
08 Feb 2017
#4
1046 hPa
07 Feb 2017
#5
1046 hPa
19 Mar 2022
Lowest pressure
958 hPa
17 Feb 2022
#2
964 hPa
10 Feb 2020
#3
964 hPa
30 Jan 2022
#4
964 hPa
05 Apr 2022
#5
965 hPa
11 Feb 2020
Highest humidity
99%
05 Apr 2018
#2
99%
04 Jul 2018
#3
99%
28 Dec 2018
#4
99%
11 May 2019
#5
99%
29 Dec 2023
Lowest humidity
1%
16 Nov 2025
#2
14%
22 May 2022
#3
19%
06 Apr 2019
#4
19%
29 Apr 2019
#5
19%
14 Mar 2022
Highest UV index
5.9
03 Jul 2025
#2
5.7
11 Jul 2021
#3
5.6
26 Jun 2021
#4
5.6
02 Jul 2025
#5
5.5
28 Jun 2020
Highest solar radiation
1088 W/m²
25 Jul 2017
#2
1068 W/m²
24 Jun 2025
#3
1044 W/m²
10 Jul 2022
#4
1042 W/m²
03 Jul 2019
#5
1036 W/m²
19 Jun 2017
Most sunshine hours
18.6 h
28 Jun 2023
#2
18.2 h
19 Jun 2023
#3
18.1 h
06 Jun 2022
#4
18.1 h
21 Jun 2022
#5
18.1 h
10 Jun 2023
Climate normals vs 2026
Departure from normal
| Month | Normal avg | Actual avg | Departure |
|---|---|---|---|
| Jan | -2.1 C | -7.5 C | -5.4 C |
| Feb | -2.1 C | -6.9 C | -4.8 C |
| Mar | 1.5 C | 4.4 C | +2.9 C |
| Apr | 5.5 C | 5.6 C | +0.1 C |
| May | 11.5 C | 11.9 C | +0.4 C |
| Jun | 16.9 C | 16.9 C | 0.0 C |
| Jul | 18.6 C | 18.1 C | -0.5 C |
| Aug | 17.8 C | 17.5 C | -0.3 C |
| Sep | -- | -- | -- |
| Oct | -- | -- | -- |
| Nov | -- | -- | -- |
| Dec | -- | -- | -- |
Compare periods
vs
vs
Highest temp
Lowest temp
Precipitation
Max wind
No data
Highest temp
Lowest temp
Precipitation
Max wind
No data