The northern French Alps are situated under the northeast corner of the Azores high pressure and have an excellent annual climate. There is good snow in winter, summer is hot with light winds and there is no excessive precipitation.
High Alpine regions create their own weather patterns or micro-climates and weather blisters form over some areas sheltering them from outside influences and only powerful weather systems will infiltrate, causing complete but temporary changes. It's rare to encounter poor weather for more than a few days at a time!
As
the majority of the flying is made in purely thermic conditions, where
thermals are created by the warm sunshine and reasonable lapse rates we are
not waiting for the wind conditions to be just right before flying. In fact
we are not concerned by the wind direction as all of our sites are for
thermic flying. However in some valleys afternoon dynamic or ridge flying
forms where the terrain allows.
Most of the year the meteo winds are light and the valley winds formed from rising thermic air blow most afternoons. Strong afternoon valley winds are only found in deep and narrow valleys when conditions are unstable. Wide open areas encounter much lighter afternoon valley wind conditions.
The mid winter flying window is around 2-3 hours extending to 11 hours in the spring and summer. Some mid summer days have strong thermic periods where pilots become grounded for a few hours, otherwise the annual flying conditions are very good. It has to be said that not all the days produce fantastic flying conditions but it's not bad here and better than many popular flying spots.
Below is a summary of the days flown each month from December to October, our working months. As you can see the overall number doesn't change dramatically each year: the chart speaks for itself.
| Date | Dec | Jan | Feb | Mar | Apr | May | June | July | Aug | Sept | Oct | Total |
| 1996 | n/a | 20 | 15 | 23 | 25 | 16 | 22 | 20 | 21 | 26 | 20 | 208 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1997 | 11 | 17 | 17 | 26 | 25 | 24 | 21 | 25 | 27 | 27 | 20 | 240 |
| 1998 | n/a | 19 | 26 | 19 | 17 | 30 | 24 | 24 | 27 | 19 | 15 | 220 |
| 1999 | 17 | 13 | 11 | 18 | 19 | 23 | 23 | 29 | 22 | 24 | 17 | 216 |
| 2000 | 2 | 22 | 13 | 17 | 18 | 26 | 26 | 17 | 25 | 25 | 19 | 210 |
| 2001 | 19 | 14 | 14 | 10 | 17 | 28 | 20 | 25 | 25 | 19 | 28 | 219 |
| 2002 | 17 | 30 | 12 | 22 | 23 | 17 | 27 | 22 | 23 | 27 | n/a | 220 |
| 2003 | 11 | 17 | 20 | 28 | 20 | 22 | 27 | 24 | 26 | 22 | 16 | 233 |
| 2004 | 15 | 6 | 21 | 16 | 22 | 22 | 25 | 26 | 27 | 27 | 19 | 226 |
| 2005 | 19 | 20 | 16 | 25 | 17 | 26 | 28 | 27 | 20 | 27 | 25 | 250 |
| 2006 | 4 | 24 | 17 | 12 | 19 | 23 | 30 | 30 | 19 | 23 | 20 | 221 |
| 2007 | 18 | 16 | 13 | 21 | 30 | 21 | 25 | 23 | 24 | 22 | 26 | 239 |
| 2008 | 20 | 16 | 24 | 12 | 18 | 27 | 18 | 22 | 28 | 25 | 14 | 224 |
| 2009 | 12 | 17 | 10 | 20 | 25 | 18 | 18 | 27 | 28 | 29 | 27 | 231 |
| 2010 | 10 | 13 | 11 | 16 | 25 | 19 | 17* | 29 | 22* | 23 | n/a | 185 |
| 2011 | n/a | n/a | 22 | 27 | 28 | 25 | 25 | 29 | 26* | 27 | 25 | 234 |
| 2012 | n/a | n/a | n/a | 20 | 15 |
Winter..
December and January our prime skiing months
are often stable, sunny, cloudless and cold. During this period thermals
still form and the best flying is found between 13.00 - 1600hrs. The smooth
thermals suit new pilots looking for gentle conditions.
Mid winter launch conditions in the snowline can sometimes be a little
frustrating as the wind at launch can either be zero or lightly katabatic.
However, by early February the warmer lower valley airflow help to create
gentle face breezes giving better launch conditions.
By mid February lapse rates are improving and cumulus cloud starts to form
over the high mountain peaks and cloud base can be reasonably high: 2000 -
2500m asl. Thermal climb rates can be 1-2m/s on the averager. (Variometer
averager set at 20secs).
The general valley temperatures are down to -15°c
at night and up to -4°c
during the day. (some nights are colder and some days are warmer especially
in the direct sunshine) Winds are mainly light apart from those arriving
with weather fronts. Valley winds are very light!
Late Winter..
In March and early April the sun now warms the lower snow free valleys
allowing thermals to rise freely, and during the afternoon they are marked
by cumulus cloud often rising to 2500 - 3000m asl. The flying window is
longer: 11.00 - 17.00hrs. Thermal climb rates are better at 2-3 m/s.
The general valley temperatures are down to -8°c
at night and up to +23°c.
Depending upon the daily thermic conditions valley winds are becoming
stronger especially in deep and narrow valleys where care is needed early to
mid afternoon!
Spring..
During April, May and June we enter some of the best thermic months. Cloud
base reaches 3200 - 3500m asl, the atmosphere is generally unstable and the
crisp thermals have good climb rates! Thermal climb rates average 4 m/s.
The flying window extends: 10.00 - 20.00hrs, though we occasionally
experience strong lunchtime periods that ground most pilots but naturally
coincide with the traditional French lunch period of 2-3 hours...
During these months we occasionally experience late afternoon or evening
thunderstorms, though these are generally well forecasted beforehand.
The general valley temperatures are down to +5°c
at night and up to +28°c
in the day. Meteo winds are normally light, but beware of strong afternoon
valley winds in deep and narrow valleys!
Summer..
In July and to mid August the atmosphere is a little more humid and cloud
base often only reaches 2500 - 3000m asl. However the days are warm if not
hot and the flying day is long: 10.00 - 21.00hrs. By August the strong
lunchtime periods have subsided allowing air sports all through the day and
thermal climbs rates still average 3-4 m/s but lessening as August arrives.
In July evening thunderstorms are sometimes present, though generally so
well forecasted we know when to expect them!
General valley temperatures are down to +15°c
at night and up to +35°c
in the day. Those strong valley winds are still present!!
Late Summer - Autumn..
As Autumn approaches stable
air returns and by September gentle thermals and friendly cumulus rise only
to 2500 - 2800m asl. From mid August to October and into November the flying
conditions mellow allowing good flying throughout the day.
October/November flying in the
mountains is special. The golden autumn colours are glorious and the cool
dry air has an incredible freshness about it! Thermal climb rates are 2-3
m/s and decreasing, and the best flying is found in
the afternoon.
General valley temperatures are down to +7°c
at night and up to +25°c
in the day, though becoming cooler by late October. The valley winds are
gentle and short lived.
General..
Yes we do get rain and snow! It's cold here in winter and hot in summer but
we have four beautiful and reliable seasons.
In winter and spring the cold fronts that pass usually only last 2-4 days
and the snowline drops to 400m asl. By mid summer the snowline rises to
around 3000m asl: there is always snow above this level as seen on the
spectacular Mont Blanc (4810m) and surrounding high peaks.
In summer warm or occluded fronts bring just a little rain. These fronts
rarely last for more than 2-3 days and any local thunderstorms are generally
short lived often diminishing into a clear night.
As we live under high pressure our natural winds meteo winds come from the
north and are nearly always light. All valley winds (anabatic winds) turn
katabatic in the evening dropping away to nothing at night' and when
conditions allow we have superb restitution (magic lift/valley
release/glass-off) flying in the evening.
So what does this all mean..
Beginners can join a course anytime from April to
November. In spring and
summer strong thermic breezes can halt flying for a few hours during the
afternoon, though there is always extra ground training or interesting class
room work available during these periods. Later in the year, mid August
onwards it's possible to train and fly throughout the day without being
challenged by the strong summer conditions.
Newly qualified pilots visiting the mountains will find smooth conditions up
to April then after early August. However the mid summer days are long and
missing 2 - 3 hours during the middle of the day is of little consequence as
there is plenty of flying early and late in the day.
Aspiring thermal and cross country pilots should visit in the spring and mid
summer months when the conditions are at their best!