Bishkek is very hot and dry (average high 32°C in July), but has plentiful water from rivers. We found similarly hot and dry weather around Lake Issyk Kul, albeit slightly cooler than Bishkek due to being at 1600m.
As we drove higher into the mountains the vegetation became greener and extended further from the river, indicating more rainfall. During our time in the valley (base at 3000m), the weather was generally clear and cool in the mornings and clouding over with increasing winds during the day. There was rain in the afternoon every 2-3 days. Only on one day did the rain stay overnight and cloud not clear for the morning. The temperature only got below freezing on a couple of nights at base camp. The dry glaciers were generally frozen in the morning, although the wet glaciers did not freeze thoroughly. The temperature in daytime got to shorts and t-shirt weather out of the wind, but generally the cloud and cooling wind took over before it got very warm. The wind was never strong enough to be of any consequence apart from a bit of wind chill.