Five day forecast for Tryfan
| Fri 21st Sep | Weather | Temp. (C) | Feels like (C) | Rain Prob. (%) | Vis. | Hum. (%) | Wind Speed (mph) | Wind Gust (mph) | Wind Dir. | UV Index | 0000 | Heavy rain | 6 | -1 | 97 | Very poor | 100 | 36 | 47 | WNW | 0 |
| 300 | Heavy rain | 4 | -4 | 97 | Very poor | 100 | 45 | 58 | W | 0 |
| 600 | Heavy rain | 2 | -6 | 74 | Very poor | 100 | 40 | 47 | W | 0 |
| 900 | Drizzle | 3 | -5 | 84 | Very poor | 100 | 43 | 49 | WSW | 1 |
| 1200 | Heavy rain | 4 | -5 | 84 | Very poor | 100 | 51 | 63 | W | 2 |
| 1500 | Heavy rain | 5 | -3 | 73 | Good | 96 | 45 | 56 | WNW | 1 |
| 1800 | Light rain | 5 | -2 | 47 | Very good | 93 | 36 | 43 | WNW | 1 |
| 2100 | Cloudy | 4 | -2 | 36 | Excellent | 89 | 34 | 40 | WNW | 0 |
| Sat 22nd Sep | Weather | Temp. (C) | Feels like (C) | Rain Prob. (%) | Vis. | Hum. (%) | Wind Speed (mph) | Wind Gust (mph) | Wind Dir. | UV Index | 0000 | Cloudy | 3 | -3 | 8 | Excellent | 89 | 31 | 38 | WNW | 0 |
| 300 | Partly cloudy | 3 | -3 | 3 | Excellent | 87 | 27 | 31 | W | 0 |
| 600 | Cloudy | 3 | -2 | 4 | Excellent | 87 | 20 | 25 | W | 0 |
| 900 | Cloudy | 4 | -1 | 9 | Very good | 89 | 18 | 22 | WSW | 1 |
| 1200 | Cloudy | 4 | 0 | 52 | Very good | 89 | 13 | 16 | SW | 2 |
| 1500 | Heavy rain | 4 | 1 | 82 | Poor | 96 | 9 | 11 | SE | 1 |
| 1800 | Heavy rain | 4 | -1 | 79 | Very poor | 98 | 16 | 20 | E | 1 |
| 2100 | Drizzle | 4 | -1 | 55 | Poor | 98 | 20 | 27 | E | 0 |
| Sun 23rd Sep | Weather | Temp. (C) | Feels like (C) | Rain Prob. (%) | Vis. | Hum. (%) | Wind Speed (mph) | Wind Gust (mph) | Wind Dir. | UV Index | 0000 | Light rain | 5 | 0 | 59 | Very poor | 99 | 20 | 27 | E | 0 |
| 300 | Light rain | 5 | 1 | 58 | Very poor | 98 | 20 | 29 | ESE | 0 |
| 600 | Light rain | 6 | 1 | 64 | Very poor | 99 | 20 | 31 | ESE | 0 |
| 900 | Heavy rain | 7 | 2 | 84 | Poor | 97 | 27 | 45 | WSW | 1 |
| 1200 | Heavy rain | 4 | -2 | 72 | Poor | 95 | 31 | 51 | NW | 2 |
| 1500 | Heavy rain shower | 3 | -4 | 71 | Moderate | 92 | 34 | 54 | NNW | 1 |
| 1800 | Heavy rain shower | 3 | -3 | 66 | Good | 88 | 27 | 45 | NNW | 1 |
| 2100 | Light rain shower | 3 | -3 | 38 | Very good | 87 | 22 | 36 | NNW | 0 |
| Mon 24th Sep | Weather | Temp. (C) | Feels like (C) | Rain Prob. (%) | Vis. | Hum. (%) | Wind Speed (mph) | Wind Gust (mph) | Wind Dir. | UV Index | 0000 | Cloudy | 2 | -3 | 9 | Very good | 90 | 20 | 29 | NW | 0 |
| 300 | Cloudy | 2 | -3 | 5 | Very good | 92 | 18 | 27 | NW | 0 |
| 600 | Cloudy | 2 | -3 | 5 | Very good | 94 | 16 | 22 | NW | 0 |
| 900 | Cloudy | 4 | 0 | 3 | Very good | 82 | 13 | 22 | NW | 2 |
| 1200 | Cloudy | 6 | 2 | 3 | Very good | 72 | 11 | 20 | NNW | 3 |
| 1500 | Partly cloudy | 5 | 2 | 1 | Very good | 72 | 9 | 20 | NNW | 1 |
| 1800 | Sunny day | 4 | 1 | 1 | Very good | 89 | 7 | 11 | NNW | 1 |
| 2100 | Partly cloudy | 2 | -1 | 1 | Very good | 95 | 7 | 9 | SSW | 0 |
| Tue 25th Sep | Weather | Temp. (C) | Feels like (C) | Rain Prob. (%) | Vis. | Hum. (%) | Wind Speed (mph) | Wind Gust (mph) | Wind Dir. | UV Index | 0000 | Clear night | 1 | -2 | 1 | Very good | 95 | 7 | 9 | SE | 0 |
| 300 | Partly cloudy | 0 | -3 | 1 | Good | 95 | 7 | 9 | SE | 0 |
| 600 | Cloudy | 0 | -4 | 4 | Good | 95 | 9 | 13 | ESE | 0 |
| 900 | Partly cloudy | 4 | 0 | 0 | Very good | 82 | 13 | 18 | SE | 2 |
| 1200 | Sunny day | 6 | 3 | 1 | Very good | 69 | 13 | 25 | S | 3 |
| 1500 | Partly cloudy | 7 | 3 | 1 | Very good | 68 | 16 | 27 | SSW | 1 |
| 1800 | Clear night | 5 | 0 | 1 | Very good | 82 | 18 | 25 | SSW | 0 |
| 2100 | Clear night | 3 | -2 | 1 | Very good | 88 | 20 | 25 | S | 0 |
Visibility - from the Met Office site
- Very poor - Less than 1km
- Poor - Between 1-4 km
- Moderate - Between 4-10 km
- Good - Between 10-20 km
- Very good - Between 20-40 km
- Excellent - More than 40 km
UV Index - from the Met Office site
The strength of the sun's ultraviolet (UV) radiation is expressed as a 'Solar UV Index', a system developed by the World Health Organization. These Met Office forecasts include the effects of:
- the position of the sun in the sky;
- forecast cloud cover;
- ozone amounts in the stratosphere.
The solar index does not exceed 8 in the UK (8 is rare; 7 may occur on exceptional days, mostly in the two weeks around the summer solstice). Indices of 9 and 10 are common in the Mediterranean area.
The UV Index can take the following values:
1-2 Low exposure. No protection required. You can safely stay outside
3-5 Moderate exposure. Seek shade during midday hours, cover up and wear sunscreen
6-7 High exposure. Seek shade during midday hours, cover up and wear sunscreen
8-10 Very high. Avoid being outside during midday hours. Shirt, sunscreen and hat are essential
11 or over Extreme. Avoid being outside during midday hours. Shirt, sunscreen and hat essential.
Weather forecasts courtesy of the Met Office.